Answer:
proton= 17
neutron=18
electron=16
ANSWER THE FOLLOWING:
Which statement represents climate ?
According to the given statement Summer are usually hot and dry represent climate.
How would you define climate?Climate is the usual weather observed over a longer period of time in a certain location. A description of a climate includes specifics like the average temperature in each season, how much rain falls, and how much sun there is. Additionally, descriptions of the extreme are common.
Why is the climate important?Nearly every area of our life is impacted by the climate, including our food supplies, transport networks, clothing choices, and vacation destinations. It significantly affects our future, our wellbeing, and our means of subsistence. The long-term pattern of the climate in any given location is called the climate.
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Electronic Configuration of the
first 50 elements
Answer:
that is some above
Explanation:
because of the chemical reaction
Aerosol cans carry clear warnings against incineration because of the high pressures that can develop upon heating. Suppose that a can contains a residual amount of gas at a pressure of 770 Torr and a temperature of 15 ∘C . What would the pressure be if the can were heated to 1235 ∘C ?
The new pressure when the can is heated to 1235 °C is 4031.8 torr
How to determine the pressurewe'llbegin by listing out the parameters obtained from the question. This is given below:
Initial pressure (P₁) = 770 torrInitial temperature (T₁) = 15 °C = 15 + 273 = 288 K New temperature (T₂) = 1235 °C = 1235 + 273 = 1508 KVolume = ConstantNew pressure (P₂) = ?The new pressure can be obtained as illustrated below:
P₁V₁ / T₁ = P₂V₂ / T₂
Volume = contant
P₁ / T₁ = P₂ / T₂
770 / 288 = P₂ / 1508
Cross multiply
P₂ × 288 = 770 × 1508
P₂ × 288 = 1161160
Divide both sides by 288
P₂ = 1161160 / 288
P₂ = 4031.8 torr
Thus, the pressure of the can is 4031.8 torr
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Please help me the density of gasoline is 0.79 g/mL, what mass of gasoline, in kilograms, is in a full
25-gallon tank?
Answer: 74.54kg
Explanation:
Gasoline is 0.79 g/mL
1Kg/1000g x 0.79g/mL x 1000mL/1L x 1L/1.06 quarts x 4 quarts/1gallon x 25 gallons
1 x 0.79 x 1000 x 1 x 4 x 25 divided by 1000 x 1 x 1 x1.06 x 1 =74.54Kg
Lab: Newton's Laws of Motion
Does anyone have the answers to these?
Newton's laws of motion the answers to these is an object will not change its motion unless a force acts on it
In the first law an object will not change its motion unless a force acts on it and in the second law, the force on an object is equal to its mass times its acceleration and in the third law when two objects interact they apply forces to each other of equal magnitude and opposite direction and newton's second law is a quantitative description of the changes that a force can produce on the motion of a body and it states that the time rate of change of the momentum of a body is equal in both magnitude and direction to the force imposed on it
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Pablo knows that NaCl dissolves in water and that elements in the same group of the Periodic Table often have similar chemical properties. He develops a hypothesis that states: All chloride salts of group I metals are soluble in water.
He proposes to test his theory by taking a small sample of each type of salt and stirring it into a beaker of water.
What will he observe if his prediction is true?
A.
Each of the solid salts will produce bubbles when mixed with the liquid water.
B.
Each mixture of salt and water will become a different color.
C.
At least some of the solid added will cease to be visible at the bottom of each beaker.
D.
After they are stirred, each of the beakers will each feel hot to the touch.
A small sample of chloride salts of group I metals on stirring with water on a beaker, at least some of the solid added will cease to be visible at the bottom of each beaker.
Group I elements are Hydrogen, Lithium, Sodium, Potassium, Rubidium, Cesium and Francium.
When chloride salts of these elements where dissolved in water it would not produce bubbles or change colour.
In addition to that, not all salts would feel hot to touch when the beaker in which the salt was dissolved is touched. Some would feel cool. This is because of difference in the process happening between the salt and water. For example: HCl would release heat when dissolved in water – Exothermic reaction (Beaker would be hot to touch) whereas KCl would absorb heat when dissolved in water – Endothermic reaction (Beaker would be cool to touch).
One common thing about chloride salts of group I elements is that they all dissolve in water. The bond between the elements and the chloride is Ionic in nature. In the water, the bond between the molecules is covalent. The covalent bonds are stronger than ionic bonds. Thus, ionic bonds dissociate and covalent bonds would be formed with water and dissociated ions i.e., chloride salts are dissolved in water. When this happens, solid would cease to be visible at the bottom of each beaker.
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POST-LAB QUESTIONS.
Write and balance the following chemical equations:
a) Al (s) + HCl (aq) → AlCl3 (aq) + H₂ (g)
b) C10H8 (s) + O2 (g) → H₂0 (1) + CO2 (g)
c) Sodium sulfate + barium nitrate → barium sulfate + sodium nitrate
d) Calcium carbonate + heat → calcium oxide + carbon dioxide
a) 2Al (s) + 6HCl (aq) → 2AlCl3 (aq) + 3H₂ (g)
b) 2C10H8 (s) + O2 (g) → H₂0 (1) + CO2 (g)
c) 2 Na2SO4 + 2 BA(NO3)2 → 2 BA(SO4) + 2NANO3
d) CaCO3 + heat → CaO + CO2
This are the Balanced Chemical equations.
Balanced chemical equationThe chemical equation can be said to as a balanced one if there are no inequalities. Every element in this illustration of a balanced equation has the same number of atoms on the reactant and product sides.
Chemical equation that is balanced is described as one in which the number of atoms of various elements on the reactants side (left side) and that on the product side (right side) are equal.
How should a balanced chemical equation be written?The reactants and products are now placed on the left and right sides of the arrow, respectively so that they create a balanced equation. Coefficients, that appear as a number before any kind of chemical formula, represent moles of a compound.
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1.000 x 10 3 ml of a solution of H2SO4 made by adding 571.6 g of sulfuric acid to water has a density of 1.3294 g/ml. (molar mass of sulfuric acid is 98.08 g/mol)
What is the molar concentration?
From the calculation, we now obtain the molarity of the sulfuric acid to be 5.8 Mol/L
What is molar concentration?The term concentration is defined as the ratio of the number of moles to the volume of the solution. We know that unit of the molarity of the solution is the moles per liters.
We know the following;
Mass of the acid = 571.6 g
Volume of the acid = 1.000 x 10^3 ml or 1 L
Molar mass of the acid = 98.08 g/mol
Hence;
Number of moles of the acid = 571.6 g/98.08 g/mol = 5.8 moles
Molar concentration of acid = 5.8 moles/ 1 L
= 5.8 Mol/L
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Assuming the compound is dissolved in water, what is the formula for phosphorous acid?
Symbol
Name
phosphate
PO
phosphite
phosphorus
0 H3P
0 H3PO4
O HP
0 Hзроз
PO3
P
H3PO3 - is the formula for phosphorous acid
What is Phosphoric acid?Phosphoric acid is a colourless, odourless, solid, inorganic compound containing phosphorus with the chemical formula H3PO. It is usually found as an 85% aqueous solution, which is a colourless, odourless, non-volatile syrupy liquid. Phosphoric acid is part of fertilizers (80% of total use), detergents and many household cleaning products. Diluted solutions have unpleasantly sour taste; As a result, it is also used as an additive to soft drinks and other ready-to-eat foods, imparting acidic properties, and in water purification products.To learn more about Phosphoric acid, visit;
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Answer: the answer is D
Explanation: hope this helps just did it
Write a balanced equation for the complete oxidation reaction that occurs when ethylene (C2H4) burns in air.
C2H4 + 3O2 ---> 2CO2 + 2H2O
Question 2 of 10
Which type of model is described below?
Air flowing over an airplane's wing can be thought of as a river flowing around
a rock.
A. Conceptual
OB. Atomic
C. Mathematical
D. Physical
SUBMIT
Air flowing over an airplane's wing can be thought of as a river flowing around a rock Conceptual. Option A.
Air moves around the wing at about 100 knots. Slightly faster based on the profile. However, if you measure the airspeed within 1 inch of the wing surface, you'll find that the airflow slows down. When it reaches the surface of the wing, the velocity of the airflow is zero. Bernoulli's Principle helps explain how the shape of a wing gives an airplane lift.
They are shaped so that the airflow is faster at the top of the wing and slower at the bottom. Fast-moving air corresponds to low pressure, and slow-moving air corresponds to high pressure. The wing is shaped and raked so that the air moving over it moves faster than the air moving underneath. As the airspeed increases, its pressure decreases. So fast-moving air at the top exerts less pressure on the wing than slower-moving air at the bottom. The result is a wing thrust upward lift.
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A student is doing an investigation with solids, liquids, and gases. They put each substance into a large syringe and press down. The
student is not able to compress the solid or the liquid into a smaller volume. When they get to the gas, they notice that it will compress
into a smaller volume. Why are gases more compressible than liquids and solids? 100 points
How many atoms of lithium are in 1.00 g?
Answer: 8.604 x1022 atoms
Explanation:
Need of help!!
The U.S. penny has a diameter of 1.905 cm. The densities of copper and zinc are 8.96 g/cm^3 and 7.14 g/cm^3, respectively.
1. Between 1944 and 1982, the penny was made of a brass alloy that is 95% copper and 5% zinc by mass. If the mass of the penny was 3.09 g, find the volume (in cm^3) and thickness (in cm) of the penny in mm. (Assume the penny is a cylinder, V = π r^2 h)
Based on the mass composition of the penny:
the volume of the penny is 0.35 cm³the thickness of the penny is 0.12 cm\What is the density of the penny that was made of a brass alloy that is 95% copper and 5% zinc by mass?The density of the penny that was made of a brass alloy that is 95% copper and 5% zinc by mass is calculated as follows:
Density of penny = % mass of Cu * density of Cu + % mass of Zn * density of ZnThe densities of copper and zinc are 8.96 g/cm³ and 7.14 g/cm³, respectively.
Density of Penny = 95% * 8.96 + 5% * 7.14
Density of penny = 8.87 g/cm³
The volume of the penny will then be;
Volume = mass / densityvolume of penny = 3.09 / 8..87
volume of the penny = 0.35 cm³
The thickness of the penny will then be;
radius of the penny = 0.95 cm
thickness of the penny = v / π r²
thickness of the penny = 0.35 / 3.142 * 0.95²
thickness of the penny = 0.12 cm
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Calculate the pH for each case in the titration of 50.0 mL of 0.190 M HClO(aq) with 0.190 M KOH(aq). Use the ionization constant for HClO.
What is the pH before addition of any KOH?
pH=
What is the pH after addition of 25.0 mL KOH?
pH=
What is the pH after addition of 40.0 mL KOH?
pH=
What is the pH after addition of 50.0 mL KOH?
pH=
What is the pH after addition of 60.0 mL KOH?
pH=
Answer:
6.13, 7.53, 8.13, 10.25, 12.24
Explanation:
Without any KOH, the pH can be calculated using an ICE table (initial, change, equilibrium). I will assume that the pka is 7.53 since that's the value that wikipedia gives
after setting up the table the equation left should be:
[tex]\frac{x^2}{0.19-x} = 2.95*10^{-8}[/tex] - original equation
the equation can be simplified to [tex]\frac{x^2}{0.19} = 2.95*10^{-8}[/tex] since if x is really small, (0.19-x) will be pretty much equal to 0.19
solve to get x = 7.49*10^-7, and since [tex]\frac{7.49*10^{-7}}{0.19}[/tex] is very small, we don't have to calculate x with the original equation instead of approximating it with the simplified equation
since x = [H3O+], -log(x) would give us the ph, so the pH would be
-log(7.49*10^-7) = pH = 6.13
For the other problems, calculate the number of moles of each of the components
in total, we have 0.05*0.19 moles of HClO, which is 0.0095 moles.
after adding 0.025*0.19 moles of KOH (0.00475 moles), there would be 0.0095-0.00475 moles of HClO left, and 0.00475 moles of ClO- would be generated. The concentrations of both ClO- and HClO are both about equal to 0.00475/0.075 (0.075 is the total amount of liquid after adding 25 ml of KOH). The fraction simplified to 0.0633
Using the equation
pH = pKa + log([A-]/[HA]), we would get pH = 7.53 + log(0.0633/0.0633)
so pH = 7.53 after 25 mls of KOH has been added
Do a similar thing for 40 mls of KOH being added.
pH = 7.53 + log(0.0844/0.0211) = pH = 8.13
For 50 mls, an ICE table needs to be used again since the moles of base and acid are roughly equal.
The resulting solution should be equal to adding
0.05*0.19 moles of KClO to water, which would be a 0.05*0.19/0.1 molar concentration, or 0.095M
Set up an equation and use ICE:
[tex]ClO^-+H2O = > HClO + OH^-[/tex]
the Kf of this equation can be calculated by rearranging this reaction and utilizing the equation for the auto-ionization of water
[tex]HClO + H2O = > H3O^+ + ClO^-[/tex] with a Ka of 2.95*10^-8
flip the reaction to get:
[tex]H3O^+ + ClO^- = > HClO + H2O[/tex] and the Ka is 1/(2.95*10^-8) , or 33898305.1
Use the equation:
[tex]2H_2O = > H_3O^+ + OH^- , \ \ \ \ K_w = 10^{-14}[/tex]
and add the equations
[tex]2H2O + H3O^+ + ClO^- = > HClO + H2O + H3O^+ + OH^-[/tex]
the K for this equation is just 33898305.1 times 10^-14
which is 3.39*10^-7
the equation can have terms present on both sides of the equation canceled out to get
[tex]ClO^-+H2O = > HClO + OH^-[/tex] with a K of 3.39*10^-7
Set up the ICE table once more, note that the ClO- concentration is 0.095
x^2/(0.095-x) = 3.39*10^-7
approximate the equation to be:
x^2/(0.095) = 3.39*10^-7
solve for x = 0.00017945 = [OH-]
the pOH would be 3.746, and since 14 = pH+pOH,
14 = pH + 3.746
pH = 10.25
For the final equation it is much simpler. Since the moles of strong base is more than the moles of acid, the pOH can be calculated by just taking the -log of the excess base, which is 0.01*0.19 moles, or 0.01*0.19/(0.11) molar solution
The concentration of OH is 0.01*0.19/(0.11), which is 0.0173.
-log(0.0173) = pOH
pOH = 1.76
pH = 1.76 = pH = 12.24
At 30°F and atmospheric pressure, water?
A. sublimes. B. melts. C. freezes. D. deposits. E. boils.
The correct answer is to freeze. Option C.
This diffusion effect of water molecules during freezing means that applying pressure to water also lowers its freezing point. With enough pressure which makes it difficult for water molecules to spread out into the solid structure, liquid water is a few degrees below zero degrees Celsius.
When water is placed in a vacuum it freezes slower or faster than water placed in a container or freezer at normal atmospheric pressure. Atmospheric pressure does affect the freezing temperature. The higher the pressure the lower the freezing temperature. For water stored in a tank, its bottom pressure is the weight acting on a unit area of the surface on which the tank is stored.
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The term route of entry on an SDS refers to the way a _____ enters the body.
The term route of entry on an SDS refers to the way a chemicals enters the body
The Safety data sheet (SDS) means which refer to the very complete documents about the chemicals the written or printed material concerning a hazardous chemical that is prepared in accordance with the HCS and the means by which a material may gain access to the body and example is inhalation, ingestion, and skin contact and and routes on an SDS refers to the way enters the chemicals in the body
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In three to five sentences, describe how the diagram of Earth’s carbon cycle demonstrates the interactions among the biosphere (plants), the lithosphere (ground), the atmosphere (air), and the hydrosphere (water).
Based on the diagram of the carbon cycle given:
Carbon is cycled between the biosphere and plants during the processes of photosynthesis.Carbon is cycled between the biosphere and lithosphere during the death and decay of organismsCarbon is cycled between the biosphere and the hydrosphere di=uring the ocean uptake of carbon from respiring plantsCarbon is cycled between the lithosphere ad the atmosphere during the burning of fossil fuels.What is the carbon cycle?The carbon cycle is a cycle that describes the processes by which carbon is recycled between the various living and non-living components of the earth.
Carbon is an essential element required by all living organisms for their growth and development.
Also, carbon is found as part of the component of the non-living environment.
There, it is important that carbon is cycled between the various spheres of the earth.
Carbon is cycled between the biosphere (plants), the lithosphere (ground), the atmosphere (air), and the hydrosphere (water).
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Patient #5: What is the density if the length of the diaphysis sample is 8.0cm, the diameter is 3.0cm and the mass of the sample is 41g?
The density of a substance is calculated by taking the ratio of its mass and volume. The density of the diaphysis sample with a mass of 41 g is 0.725 g/cm³.
What is density?Density is measure of mass of a substance per unit volume. Thus, mathematically it is mass divided by volume. Density of a substance is dependant on molecular weight, volume, temperature and bond type also.
Density of a substance may change with temperature. For example, the density if water is 1 g/L but it changes to maximum 4° C. A diaphysis sample is cylindrical in shape and have a volume of πr²l where r is the radius and l be the length.
The volume of the diaphysis with a length of 8 cm and radius of 1.5 cm is calculated as follows:
Volume = πr²l
= 3.14 × (1.5 cm)² × 8 cm
= 56.52 cm³.
The density of the sample can be calculated by dividing the mass by volume as follows:
Density = mass / volume
= 41 g/ 56.52 cm³
= 0.725 g/cm³
Therefore, the density of the diaphysis sample is 0.725 g/cm³.
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When a 1.00 L sample of water from the surface of the Dead Sea (which is more than 400 meters below sea level and much saltier than ordinary seawater) is evaporated, 156 grams of MgCl₂ are recovered. What is the molarity of MgCl₂ in the original sample?
The What is the molarity of MgCl₂ in the original sample is 1.63 mol/L
[tex]Molarity = \frac{Mass\ of\ MgCl_2}{molar \ mass\ of MgCl_2} \times\frac{1}{volume \of \ the\ solution \ in\ litres}[/tex]
[tex]Molarity = \frac{156g}{95.211g/mol} \times\frac{1}{1L}\\\\Molarity = 1.63 \ mol/L[/tex]
What is molarity ?Molarity (M) is the amount of a substance in a certain volume of solution. Molar concentration is a measure of the concentration of chemical compounds, especially a solute in a solution, as the amount of the substance per unit volume of the solution. In chemistry, the most commonly used unit of molarity is the number of moles per litter, indicated in the SI unit mol/L or mol/dm³.
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Suppose you identify a new element, Interactium. Interactium has three isotopes: Interactium-283, Interactium-286, and Interactium-292. In the mixture, 22% of the mixture is Interactium-283, 35% is Interactium-286, and the rest of the mixture is Interactium-292.
What is the relative atomic mass for Interactium?
The relative atomic mass of the interactium, give the data is 287.92 amu
How to determine the relative atomic massThe relative atomic mass of the interactium can be obtained as illustrated below:
Mass of isotope A (Interactium-283) = 283Abundance of A (A%) = 22%Mass of isotope B (Interactium-286)= 286Abundance of B (B%) = 35%Mass of isotope C (Interactium-292)= 292Abundance of C (B%) = 100 - (22 + 35) = 43%Relative atomic mass =?Relative atomic mass = [(Mass of A × A%) / 100] + [(Mass of B × B%) / 100] + [(Mass of C × C%) / 100] +
Relative atomic mass = [(283 × 22) / 100] + [(286 × 35) / 100] + [(292 × 43) / 100]
Relative atomic mass = 62.26 + 100.1 + 125.56
Relative atomic mass = 287.92 amu
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The combustion of propane may be described by the chemical equation
C₂Hg (g) + 5O₂(g) → 3 CO₂(g) + 4H₂O(g)
-
How many grams of O₂(g) are needed to completely burn 27.6 g C3H₂(g)?
According to the given statement 4.64 grams of O₂(g) are needed to completely burn 27.6 g C₃H₂(g).
What is called chemical equation?Chemical equations are symbolic depictions of chemical reactions where the reactants and products are stated in terms of their respective chemical formulae.
Briefing:Mass of C₃H₂ = 27.6 g
Molar mass of C₃H₂ = 38.05 g/mol
Molar mass of O₂= 32 g/mol
We have to calculate the moles of C₃H₂
moles of C₃H₂ = given mass C₃H₂/molar mass C₃H₂
moles of C₃H₂ = 27.6/38.05 = 0.725 mol
We have to calculate the moles of C₃H₂
The balanced chemical equation is:
C₂Hg (g) + 5O₂(g) → 3 CO₂(g) + 4H₂O(g)
From the reaction, we conclude that
As, 1 mole of C₂Hg react with 5 mole of O₂
So, 0.725 mole C₃H₂ of react with 0.725/5 = 0.145 mole of O₂
We have to calculate the mass of O₂
Mass of O₂ = Moles of O₂ * Molar mass of O₂
Mass of O₂ = (0.145moles) * (32g/mol) = 4.64g
The mass of O₂ needed is, 4.64 grams.
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Solve the following calculations:
Calculation also includes applying logic to a non-numerical issue. Exponentiation comes first, followed by multiplication and division, and then addition and subtraction, as is the case for each mathematical equation.
What is meant by calculation?
A computation is a methodical, well-thought-out process. Calculating the solution to a math problem is the first type of calculation, for which you might use a calculator. Calculation also includes applying logic to a non-numerical issue.
Exponentiation comes first, followed by multiplication and division, and then addition and subtraction, as is the case for each mathematical equation.
1 km = 1000 m; 1 hr = 3600 sec.
[1 km/hr = 1000/3600 m/sec = 5/18 m/sec
To convert km/hr into m/sec, multiply the number by 5 and then divide it by 18.]
83km.h-1 = 83 × 5/18 = 23.05
= 23 m.s-1
83 km.h-1 + 83 m.s-1 = 23 m.s-1 + 83 m.s-1
= 106 m.s-1
Therefore, the correct answer is 106 m.s-1.
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Which statement about subtatomic particles are true
The statement about sub-atomic particles that is true is:
Electrons are the subatomic particles with the smallest mass; option BWhat are sub-atomic particles?Sub-atomic particles refer to the smaller particles that are the constituents of atoms of elements.
There are three sub-atomic particles within a given atom,
The three sub-atomic particles are given below:
electrons -electrons are the negatively charged particles found outside the nucleus of an atom in electron shells or orbitals around the atom.protons - these are positively charged particles found inside the nucleus of an atom. The number of protons in an atom gives the atomic number of that atom.neutrons - these are neutral atoms found in the nucleus of atoms. The sum of the neutrons and protons in the nucleus of an atom gives the mass number of an atom. This is because the mass of an at is centered inside the nucleus since the proton and neutron have equal mass but the electron has negligible mass.Considering the given statements about the sub-atomic particles, the only true statement is that which describes the mass of the electron as being the smallest of the three sub-atomic particles.
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Complete question:
Which statement about subatomic particles is true?
Protons are the only subatomic particles to have a charge.
Electrons are the subatomic particles with the smallest mass.
Neutrons orbit the nucleus of the atom.
Subatomic particles all have the same mass
How would I go About solving this with a chart?
Atomic Structure - Dalton's Atomic Theory
From Dalton's experiments and observations, and from the work of some of his colleagues he proposed a new theory of the atom.
Answer:
For answering we will have to create a 5x3 table. It will have the following headings:
The information that has to go in the table is:
Dalton's Postulates
1.1:All matter is composed of extremely small particles called atoms.
2.1: Atoms of a given element are identical in size, mass, and other properties. Atoms of different elements differ in size, mass and other properties.
3.1: Atoms cannot be subdivided, created or distroyed.
4.1 Atoms of different elements can combine in simple whole number ratios to form chemical compounds.
5.1: In chemical reactions, atoms are combined, separated or rearranged.
Keep/Modify/Discard:
1.2:Keep
2.2:Modify
3.2:Modify
4.2:Keep
5.2:Keep
Rewrite in case of need:
1.3: No need
2.3: Atoms of different elements differ in size, mass and other properties. Atoms of a given element can also differ in mass.
3.3: Atoms can be further subdivided, and using nuclearfission and fussion techniques atoms can be created or destroyed by changing them into other atoms.
4.3:No need
5.3: No need
The concentration of glucose (molar mass 180 g/mol) in the fluid of the spine is 75 mg / 100g of water. What is the molal concentration?
Considering the definition of molal concentration, the molal concentration of glucose is 0.004166 moles/kg.
Molal concentration or molalityMolality or molar concentration is a way of measuring the concentration of solute in solvent, that is, the number of moles of solute present in the solvent.
Molality is defined as the moles of a solute per kilogram of solvent.
The Molality of a solution is determined by the expression:
molality= number of moles of solute÷ kilogram of solvent
Molala concentration in this caseIn this case, you know:
Molar mass of glucose= 180 g/molConcentration of glucose= 75 mg/ 100 g of waterMass of glucose= 75 mg= 0.075 g (being 1 mg= 0.001 g) Number of moles of solute= Mass of glucose÷ Molar mass of glucose= 0.0004166 molesMass of solvent = Mass of water= 100 g= 0.1 kg (being 1000 g= 1 kg)Replacing in the definition of molal concentration:
molality= 0.0004166 moles÷ 0.1 kg
molality= 0.004166 moles/kg
Finally, the molal concentration in this case is 0.004166 moles/kg.
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A sample of cigarette smoke contains 2.40% carbon monoxide. The U.S. national ambient air quality standard for CO in a 1-hr period is 35.0 ppm.
How many times greater than this standard is the CO concentration in cigarette smoke?
The cigarette smoke as it were is 686 times greater than the standard.
What is concentration?The term concertation is used to describe the amount of substance that is contained in a sample. There are several units that could be used in the measurement of concentration such as;
NormalityParts per million Parts per billionMolarityMolalityIn this case, the designation 35.0 ppm means 35 units of carbon monoxide in 1,000,000 units, this is the same as saying 3.5 x 10^-5.
Again we have the percent concentration of the sample as 2.40% or 0.024. Hence we would get the number of times greater than this standard is the CO concentration in cigarette smoke is by;
0.024/ 3.5 x 10^-5
= 686
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if you start the reaction with 10 g of plantinum, 180 mL of 5 M HCL, and 223 mL of 6.55 M HNO3, how much H2PtCl6 would be formed
A reaction that starts with 10 g platinum, 180 mL 5 M HCl, and 223 mL 6.55 m [tex]HNO_3[/tex] will produce 20.9 grams of [tex]H_2PtCl_6[/tex].
Stoichiometric problemFirst, let's look at the equation of the reaction:
[tex]3 Pt + 4 HNO_3 + 18 HCl -- > 3 H_2[PtCl_6] + 4 NO + 8 H_2O[/tex]
The mole ratio of Pt, [tex]HNO_3[/tex], and HCl from the balanced equation of the reaction is 3:4:18.
Mole of 10 g platinum = 10/195
= 0.051
Mole of 180 mL, 5 M HCl = 180/1000 x 5
= 0.9 moles
Mole of 223 mL, 6.55 M [tex]HNO_3[/tex] = 223/1000 x 6.55
= 1.46 moles
Considering the mole ratio, HCl seems to be in excess while both platinum and [tex]HNO_3[/tex] are limiting.
Mole ratio of platinum and [tex]H_2PtCl_6[/tex] = 1:1
Equivalent mole of [tex]H_2PtCl_6[/tex] that is produced = 0.051 moles.
Mass of 0.051 mole platinum = 0.051 x 409.81
= 20.9 grams
Thus, the amount of [tex]H_2PtCl_6[/tex] that would be formed is 20.9 grams.
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What is the equation for the base dissociation constant, Kb, of NH3?
NH,(aq)+H,O(l)
The formula for the base dissociation constant (Kb) is Kb = [NH4+][OH-]/[NH3].
Briefing :Kb is a temperature-dependent constant that is typically calculated at 25 degrees Celsius. Ammonia has a Kb value of 1.8E-5 (the notation "E-5" stands for "ten in power -5").
What causes NH3 to dissociate?A basic solution is created when ammonia and water are combined. Ammonium hydroxide is created when a little amount of dissolved ammonia combines with water. This compound then breaks down into ammonium and hydroxide ions.
What is the base dissociation constant?A material that absorbs hydrogen ions or protons in solution is referred to as a base. The base dissociation constant is the equilibrium constant for the equilibrium created when a weak base interacts with water.
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