Answer:
Test it with a blue light that is 45 cm away.
Explanation:
Find the Protons and Electrons for nitrogen -3 ion with 7 neutrons.
Answer:
protons: 7; electrons: 10
Explanation:
nitrogen atomic number=# of protons = 7 (doesn't change either in ion or in neutral)
# of electron in neutral N=7
N-3= three electrons are added, thus 7+3=10
A student takes a stock solution that is 50 mM (solute formula weight is 120.5 g/mol) and prepares a series of solutions. The first solution is made by diluting 1 mL of the stock in water to a final volume of 15 mL (sample 1). They then take a 2 mL aliquot of sample 1 and dilute in water to a final volume of 25 mL (sample 2). Finally, they take a 1.5 mL aliquot of sample 2 and dilute to a final volume of 250 mL. Calculate the final molar concentration for the analyte in molarity, molality, ppm, and ppb. State any assumptions.
Answer:
1.6x10⁻⁶M
1.6x10⁻⁶m
0.1928ppm
192.8ppb
Explanation:
The first dilution of the solution is from 1mL to 15mL. The second from 2mL to 25mL and the third from 1.5mL to 250mL. That means molarity is:
50mM =
0.050M * (1mL / 15mL) * (2mL / 25mL) * (1.5mL / 250mL) = 1.6x10⁻⁶M
Molality is defined as the ratio between moles and kg. Assuming the density of the solution is 1kg/L, molality is 1.6x10⁻⁶m
ppm is the ratio between milligrams and Liters:
1.6x10⁻⁶mol / L * (120.5g /mol) * (1000mg / g) = 0.1928mg/L = 0.1928ppm
And ppb = 1000*ppm;
0.1928ppm*1000 = 192.8ppb
A chemist adds 0.60L of a 0.20/molL sodium thiosulfate Na2S2O3 solution to a reaction flask. Calculate the millimoles of sodium thiosulfate the chemist has added to the flask. Round your answer to 2 significant digits. (in mmol)
Answer:
1.2×10² mmole of Na₂S₂O₃
Explanation:
From the question given above, the following data were obtained:
Volume = 0.6 L
Molarity = 0.2 mol/L
Mole of Na₂S₂O₃ =?
Molarity is simply defined as the mole of solute per unit litre of water. Mathematically, it is expressed as:
Molarity = mole /Volume
With the above formula, we can obtain the number of mole of Na₂S₂O₃ in the solution as illustrated below:
Volume = 0.6 L
Molarity = 0.2 mol/L
Mole of Na₂S₂O₃ =?
Molarity = mole /Volume
0.2 = Mole of Na₂S₂O₃ / 0.6
Cross multiply
Mole of Na₂S₂O₃ = 0.2 × 0.6
Mole of Na₂S₂O₃ = 0.12 mole
Finally, we shall convert 0.12 mole to millimole (mmol). This can be obtained as follow:
1 mole = 1000 mmol
Therefore,
0.12 mole = 0.12 mole × 1000 mmol / 1 mole
0.12 mole = 120 = 1.2×10² mmole
Thus, the chemist added 1.2×10² mmole of Na₂S₂O₃
A 250 grams sample of an unknown substance was heated from 35 degree Celsius to 50 degree Celsius. The substance absorbed 7,454 J of energy. What is the specific heat of the substance? Identify if the reaction is exothermic or endothermic
Answer:
Specific heat capacity, c = 1.99J/g°C. The reaction is endothermic because heat is being absorbed.
Explanation:
Given the following data;
Mass = 250g
Original temperature, T1 = 35°C
New temperature, T2 = 50°C
Quantity of heat = 7454J
To find the specific heat capacity;
Heat capacity is given by the formula;
[tex] Q = mcdt[/tex]
Where;
Q represents the heat capacity or quantity of heat.
m represents the mass of an object. c represents the specific heat capacity of water. dt represents the change in temperature.dt = T2 - T1
dt = 50 - 35
dt = 15°C
Making "c" the subject of formula, we have;
[tex] c = \frac {Q}{mdt} [/tex]
Substituting the values into the equation, we have;
[tex] c = \frac {7454}{250*15} [/tex]
[tex] c = \frac {7454}{3750} [/tex]
Specific heat capacity, c = 1.99J/g°C.
Therefore, the reaction is endothermic because heat is being absorbed (initial temperature is lower than the final temperature).
Which is an example of maintaining structure?
Question 4 options:
healing a wound
sweating
all answers are examples of maintaining structure
keep from getting too cold
Answer: healing a wound
Explanation:
The healing of the wound is the example of maintenance of the structure. The wound is the injury which disturbs the continuity of the skin surface. It can affect the dermal and epidermal layer of the skin. The wound if severe or deep can damage the bones. The wound can be caused by the cut, blow or punch, impact or fall from height. The healing of the wound may take several days to weeks. The wound healing involves the replacement of the damaged or destroyed cells or tissues by new cells or tissues in the body or the wound site.
Analyze: What pattern do you see? Make a rule: Based on your data, how are elements arranged into chemical families?
Answer: in order of increasing atomic number.
Explanation: Elements in the same group have similar chemical properties. This is because they have the same number of outer electrons and the same valency.
Answer:
What pattern do you see?
Chemical families have the same number of valence electrons.
Make a rule: Based on your data, how are elements arranged into chemical families?
They are arranged vertically depending on how many valence electrons they have, if they have the same amount, they will have the same chemical family in each column.
How many grams of sodium chloride should you theoretically produce if you start with 5.00 grams of calcium chloride and excess sodium carbonate? (answer in numbers only - no units or words)
Answer:
5.27 g of NaCl
Explanation:
The balanced equation for the reaction is given below:
Na₂CO₃ + CaCl₂ —> 2NaCl + CaCO₃
Next, we shall determine the mass of CaCl₂ that reacted and the mass of NaCl produced from the balanced equation. This can be obtained as follow:
Molar mass of CaCl₂ = 40 + (35.5×2)
= 40 + 71
= 111 g/mol
Mass of CaCl₂ from the balanced equation = 1 × 111 = 111 g
Molar mass of NaCl = 23 + 35.5
= 58.5 g/mol
Mass of NaCl from the balanced equation = 2 × 58.5 = 117 g
Summary:
From the balanced equation above,
111 g of CaCl₂ reacted to produce 117 g of NaCl.
Finally, we shall determine the theoretical yield of NaCl. This can be obtained as follow:
From the balanced equation above,
111 g of CaCl₂ reacted to produce 117 g of NaCl.
Therefore, 5 g of CaCl₂ will react to produce = (5 × 117)/111 = 5.27 g of NaCl.
Thus, the theoretical yield of NaCl is 5.27 g.
To isolate a single variable when re-arranging equations, move all other variables to the_____of the equation by using the____on them and remembering to perform that operation_____. Make sure the rearrangement has the target variable_____.
a. on the left side, not the right side.
b. in the numerator, not the denominator.
c. with a coefficient, not without one.
d. with a negative sign, not a positive sign.
Answer:
Other side
Opposite function
On both sides of the equation
In the numerator and not the denominator
Explanation:
To isolate a single variable when rearranging equations, move all other variables to the other side of the equation by using the opposite function on them and remembering to perform that operation on both sides of the equation. Make sure the rearrangement has the target variable in the numerator, not the denominator.
If 9.5 × 10²⁵ molecules of CO₂ are produced in a combustion reaction, what is the mass in kg of CO₂ that is produced?
Answer:
6.9428 kg of CO2
Explanation:
1) Use Avogadro's number that states 1 mole = 6.022 x 10^23 particles. Convert 9.5 x 10^25 molecules into moles.
9.5 x 10^25 CO2 molecules[tex]x\frac{1 mole CO2}{6.022 x 10^23}[/tex] = 157.75 moles CO2
2) Convert 157.75 moles of CO2 into grams. CO2's molar mass is 44.01g.
[tex]157.75moles CO2[/tex] [tex]x \frac{44.01g/mol}{1 mole CO2}[/tex] = 6942.79g
3) Convert 6942.79 grams into kilograms (divide by 1000):
6.9428 kg
chemistry
Definition in your own words. I will check if you got it from online.
Word:
Malleable
(malleability)
Which rule states that cracks on glass tend to form at a certain angle on the opposite side of the polnt of Impact?
The
rule states that cracks tend to form at a (n)
angle on the opposite side from the point of Impact.
Answer:
The 3R rule states that cracks tend to form at a (n) right angle on the opposite side from the point of impact.
Explanation:
Which is the closest antonym for the word enhance?
A prolong
guarantee
C
diminish
salvage
Answer:
C. Diminish.
Explanation:
An antonym is the opposite meaning of a given word. It is the word that gives the complete opposite meaning of the given word.
The word "enhance" means "to increase, intensify, magnify, to make it more than it already is" etc. So, the antonym of that word will be "to diminish, to reduce, to prevent" etc.
Thus, the correct answer is option C.
A sample of N2O4(g) is placed in an empty cylinder at a certain temperature. It is allowed to decompose and form NO2(g). At equilibrium, the flask has a total pressure of 1.000 atm. If the KP at this temperature is 0.85, calculate the partial pressure (in atm) of NO2(g) at equilibrium. g
Answer:
Part. press. NO₂ in equilibrium is 0.590 atm
Explanation:
First of all, we determine the equilibrium:
N₂O₄ (g) ⇄ 2NO₂ (g)
These is a system of two unknown values.
In the begining we have x pressure of N₂O₄ and no value for NO₂.
During the reaction, y pressure has been released from N₂O₄. As ratio is 1:2, 2y will be the value for the pressure of NO₂. So in the equilibrium we have:
N₂O₄ → x - y
NO₂ → 2y
Data from the excersise states that the total pressure is 1 atm so we know that the sum of partial pressures in a mixture, will be the total one. In the equilibrium, total pressure will be:
(x-y) + 2y = 1 atm
x + y = 1 atm
Let's make the expression for Kp
Kp = [Partial pressure NO₂]² / [ Partial pressure N₂O₄]
Kp = (2y)² / (x-y)
Kp = 4y² / (x-y)
We split the x value in the first equation:
x + y = 1 atm
x = 1 atm - y
x = 1 - y → we put this in the Kp expression
0.85 = 4y² / ( 1 - y - y)
0.85 = 4y² / 1 -2y
This is a quadractic equation
0.85 - 1.7y - 4y² = 0 where (a = -4, b = -1.7 c = 0.85)
(-b +- √(b² - 4ac)) / (2a)
(1.7 +-√((-1.7)² - 4 (-4) . 0.85) / 2 .(-4) → 0.295 = y
As [ Part. press. NO₂] in equilibrium is 2y → 0.295 . 2 = 0.590 atm
Based on the total pressure at equilibrium, the partial pressure NO₂ of at equilibrium is 0.590 atm.
What are the partial pressures of the gasses at equilibrium?From the equation of the reaction, the equilibrium is determined:
N₂O₄ (g) ⇄ 2NO₂ (g)At equilibrium, N₂O₄ and NO₂ exist in the ratio 1 : 2.
N₂O₄ at x pressure releases y pressure to form NO₂ .
Thus at equilibrium:
N₂O₄ → x - y
NO₂ → 2y
Ptotal = 1 atm
Thus:
(x-y) + 2y = 1 atm
x + y = 1 atm
Also, Kp = 0.85
From the equation of the reaction:
Kp = [Partial pressure NO₂]² / [ Partial pressure N₂O₄]
Kp = (2y)² / (x-y)
Kp = 4y² / (x-y)
Solving for x from the first equation:
x + y = 1 atm
x = 1 atm - y
Substitute x = 1 - y in the Kp expression
0.85 = 4y² / ( 1 - y - y)
0.85 = 4y² / 1 -2y
0.85 - 1.7y - 4y² = 0
Solving the quadractic equation:
where a = -4, b = -1.7 c = 0.85
y = (-b +- √(b² - 4ac)) / (2a)
y =(1.7 +-√((-1.7)² - 4 (-4) × 0.85) / 2 × (-4)
y = 0.295 or y = -0.720
We take positive value of y only.
Since partial pressure of NO₂ in equilibrium is 2y
Partial pressure of NO₂ = 0.295 × 2
Partial pressure of NO₂ = 0.590 atm
Therefore, the partial pressure of at equilibrium is 0.590 atm.
Learn more about about equilibrium partial pressure at: https://brainly.com/question/7183826
Identify the true statements about surface tension. Molecules along the surface of a liquid behave differently than those in the bulk liquid. Water forming a droplet as it falls from a faucet is a primary example of surface tension. Surface tension increases as the temperature of the liquid rises. Cohesive forces attract the molecules of the liquid to one another. Mercury has a lower surface tension than water.
Answer:
Molecules along the surface of a liquid behave differently than those in the bulk liquid.
Cohesive forces attract the molecules of the liquid to one another.
Water forming a droplet as it falls from a faucet is a primary example of surface tension.
Explanation:
Surface tension is the force that stretches the liquid surface. This force acts normal to the surface. It is the downward force that acts on the surface of the liquids which is due to the cohesive forces of the liquids.
The water molecules are bonded by a strong hydrogen bond force which is between hydrogen atom and the electronegative oxygen atom. At the surface the water molecules are attracted strongly by other water molecules which lies below the surface and are stretched at the surface. Thus the water molecules at the surface acts differently than in the bulk liquid.
Mercury have a strong cohesive force than the water and have a higher surface tension force than the water.
Surface water acquires minimum surface area, hence acquiring spherical shape of water.
50 + 50 - 25 x 0 + 5 + 5 =
Write a description of how you know a chemical reaction is occurring.
ANSWER FAST FIRST PERSON GETS BRAINLIEST
Answer:
See explanation
Explanation:
Chemical reactions are also referred to as chemical change. A chemical change often leads to the formation of new substances and is not easily reversible.
A chemical reaction may be accompanied by the emission of heat and light, formation of a precipitate, evolution of gas, or a color change.
These observable physical effects may tell us weather a chemical reaction has taken place or not so we have to observe the system closely for any of these effects stated above.
A 0.0250L solution of HCl is neutralized by 0.0780L of an unknown Mg(OH)2 solution. Also 0.050L of this Mg(OH)2 solution is neutralized by 0.0300L of a 0.20 M H3(PO3) solution. What is the concentration of the HCl solution
Answer:
[tex]M_{HCl} = 1.12M[/tex]
Explanation:
Hello!
In this case, for the first reaction we need to focus on, the neutralization of magnesium hydroxide by phosphoric acid, we can write up the following equation:
[tex]3Mg(OH)_2+2H_3PO_4\rightarrow Mg_3(PO_4)_2+6H_2O[/tex]
Whereas the acid and base react in a 3:2 mole ratio; thus, we can write:
[tex]2M_{Mg(OH)_2}V_{Mg(OH)_2}=3M_{H_3PO_4}V_{H_3PO_4}[/tex]
Now, solving for the concentration of the magnesium hydroxide solution we get:
[tex]M_{Mg(OH)_2}=\frac{3M_{H_3PO_4}V_{H_3PO_4}}{2V_{Mg(OH)_2}} \\\\M_{Mg(OH)_2}=\frac{3*0.20M*0.0300L}{2*0.050L}=0.18M[/tex]
Now, for the reaction between hydrochloric acid and magnesium hydroxide we have:
[tex]Mg(OH)_2+2HCl\rightarrow MgCl_2+2H_2O[/tex]
[tex]2M_{Mg(OH)_2}V_{Mg(OH)_2}=M_{HCl}V_{HCl}[/tex]
Therefore, solving for the concentration of the hydrochloric acid solution we get:
[tex]M_{HCl}=\frac{2M_{Mg(OH)_2}V_{Mg(OH)_2}}{V_{HCl}} \\\\M_{HCl}=\frac{2*0.18M*0.078L}{0.025L}\\\\M_{HCl} = 1.12M[/tex]
Best regards!
Draw three different Lewis structures that could be possible for ZX2, assuming that Z is the central atom and that X is not hydrogen. Both Z and X obey the octet rule. Give molecular shapes and bond angles for each structure drawn. In each case, use valence shell electron pair repulsion theory to explain why the molecular shape is possible.
Answer:
See images attached and explanation
Explanation:
I have drawn three possible structures of ZX2. We have to remember that the shapes of molecules could be predicted on the basis of the Valence shell electron pair repulsion theory.
The number of electrons on the valence shell of the central atom determines the shape of the molecule. We have also been told that X is not hydrogen.
If the two X atoms are arranged at a bond angle of 180 degrees, we could have either structure I or II. We will have these structures if the Z atom is sp2 hybridized.
Similarly, if the Z atom is sp3 hybridized, we may have structure III in which the molecule is bent with a bond angle less than 109 degrees. This may result from the presence of a lone pair on Z.
Note that all these structures obey the octet rule.
helppp nowww plsss rnnn!
Suppose a 500.mL flask is filled with 0.40mol of N2 and 1.0mol of NO. The following reaction becomes possible:
N2g+O2g ->2NOg
The equilibrium constant K for this reaction is 5.93 at the temperature of the flask. Calculate the equilibrium molarity of N2. Round your answer to two decimal places.
Answer:
[N₂] = 1.1M
Explanation:
Based on the chemical reaction:
N₂(g) + O₂(g) ⇄ 2 NO(g)
Equilibrium constant, K, is defined as:
K = 5.93 = [NO]² / [N₂] [O₂]
Where [] are equilibrium concentrations of each specie
As initial concentrations are:
N₂ = 0.40mol / 0.500L = 0.8M
NO = 1mol / 0.500L = 2M
The equilbrium concentrations are:
[NO] = 2M - 2X
[N₂] = 0.8M +X
[O₂] = X
Replacing:
5.93 = [2 - 2X]² / [0.8+X] [X]
5.93 = 4 - 8X + 4X² / 0.8X + X²
4.744X + 5.93X² = 4 - 8X + 4X²
1.93X² + 12.744X - 4 = 0
Solving for X:
X = -6.9M → False solution. There are no negative concentrations
X = 0.3M. Real solution.
[N₂] in equilibrium is:
[N₂] = 0.8M +0.3M
[N₂] = 1.1M
A chemical reaction takes place inside a flask submerged in a water bath. The water bath contains 6.50kg of water at 24.2°C. During the reaction 88.2kJ of heat flows out of the flask and into the bath.Calculate the new temperature of the water bath. You can assume the specific heat capacity of water under these conditions is 4.18·J·g−1K−1. Be sure your answer has the correct number of significant digits.
Answer:
27.4°C
Explanation:
Using the equation:
Q = m*C*T
Where Q is heat added,
m the mass of water
C specific heat of water (4.18J/g°C)
And T the increase in temperature
We can solve for the increase in temperature and thus, the final temperature of water:
Q = 88200J; m = 6500g:
88200J = 6500g*4.18J/g°C*T
3.2°C = T = increase in temperature
Final temperature is:
24.2°C + 3.2°C =
27.4°CA and B react according to the scheme 2A + B C. The reaction is highly exergonic, that is, it goes to completion when A and B are allowed to react. In order to achieve the exact stoichiometry, your intention is to mix in a kettle 2.000 tons of A and 1.000 ton of B. A balance, the maximum capacity of which is 0.500 tons with 1% precision was used to weigh A and B. Assume that the molar masses of all chemical species are equal. What is the maximum possible amount of unreacted reactants?
Answer:
0.03 tons
Explanation:
From the given information, for every 0.500 tons of A and B, the maximum amount on weighing them will be:
1% of 0.5 = 0.005
Thus, for 2 tons of A; we have:
0.005 × 4 = 0.02
and, for 1 ton of B; we have:
0.005 × 2 = 0.01
However, after taking the precision into account;
The number of tons of A that reacted is = (2 - 0.002) = 1.98 tons of A
The number of tons of B that reacted is = ( 1 - 0.01) = 0.99 tons of B
So, 1.98 tons of A reacted with 0.99 tons of B to form 0.99 tons of C.
∴
For unreacted reactants, The maximum possible amount is (0.02 + 0.01) tons = 0.03 tons
How many F atoms are in this compound? 6MgF2 12 6 8 2
Answer:
5.0×1022 sa taas po yang 22
Which of the following is the least important property of a mineral?
A streak
B hardness
C luster
D color
Explanation:
Türküm lben .Türk varmi kardaşlar!!!
Answer:
D color
Explanation:
One physical test for minerals is to check their color. Certain kinds of minerals always have a similar color, but most minerals have a range of colors. This is the least informative property of a mineral. Some words to describe color are: pale, bright, streaked, splotchy, banded, and speckled.
This is from my school assignment good luck everyone!! :D
When H2(g) reacts with F2(g) to form HF(g) , 542 kJ of energy are evolved for each mole of H2(g) that reacts. Write a balanced thermochemical equation for the reaction with an energy term in kJ as part of the equation. Note that the answer box for the energy term is case sensitive. Use the SMALLEST INTEGER coefficients possible and put the energy term (including the units) in the last box on the appropriate side of the equation. If a box is not needed, leave it blank.
Answer:
[tex]H_2+F_2\rightarrow 2HF+542 kJ[/tex]
Explanation:
Hello!
In this case, since exothermic reactions evolve or release energy when undergone, we infer that the energy is part of the products as it is a result of the reaction; thus, for the described reaction we should set it up as follows:
[tex]H_2+F_2\rightarrow 2HF+542 kJ[/tex]
However, if the reaction absorbs energy, the energy associated to the reaction is put at the reactants side, keeping in mind that it would be an endothermic reaction.
Best regards!
What kind of atoms An attachment
How many moles are there in 100.0 grams of KMnO4
Answer:
the answer rounded to the nearest hundredth is 0.63
Explanation:
PLZ HELP ASAP WILL GIVE BRAINLISTS TO RIGHT ANSWER
How many molecules of carbon dioxide are in 12.2 L of the gas at STP?
A) 3.28 x 10^23 molecules
B) 5.01 X 10^23 molecules
C)2.24 x 10^23 molecules
D)8.12 x 10^22 molecules
Answer:
c
Explanation:
ok than not c than b maybe
PREDICT How do you think the atoms in metal elements are different from those in
nonmetals or metalloids? How might the atoms of different metals vary from one another?
Answer:
See explanation
Explanation:
The atoms of metals have fewer valence electrons than the atoms of metals and metalloids.
Atoms of metals have only very few valence electrons in their outermost shells hence they donate electrons during bonding. However, atoms of nonmetals have more electrons in their outermost shells and rather accept electrons during bonding. The atoms of metalloids just have a number of valence electrons that are intermediate between those of metals and nonmetals and mostly share electrons in covalent bonds.
Similarly, atoms of metallic elements differ from each other in the number of valence electrons present in the valence shell of the atom of each element. For instance, sodium has one electron in the valence shell of its atom while aluminium has three electrons in the valence shell of its atom.
The atoms of metallic elements are different from the atoms of non metals or metalloids base on the outer electron/ valency electrons and the its bonding pattern.
The atoms of different metals varies in it ability to bond quickly.
The atoms of metallic elements are different from the atoms of non metals or metalloids base on the outer electron/ valency electrons and how it bonds.
Metallic atoms have very few electrons in the outermost shell. The valency electrons of this metallic atoms are few and are easily lost during bonding. They have the ability to release there valency electrons easily. Example of this metals are sodium, potassium , calcium etc.
On the other hand non metallic elements have numerous electron in the outermost shell and easily receive electron during bonding. Example are chlorine, fluorine, oxygen etc.
The metalloid atoms like silicon and germanium have an average number of electron in their outermost shell. They are in between.
The atoms of different metals varies in it ability to bond quickly. For example the group 1 metals are very reactive than the group 2 metals. This simply means the group 1 metals(alkali metals) goes into bonding more easily than the group 2 metals(alkali earth metals).
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What is the empirical formula of a compound that is composed of 60.94% carbon 15.36% hydrogen and 23.70% nitrogen
Answer:
C₃H₉N
Explanation:
The empirical formula of a compound is the fundamental and basic possible formula that shows the mole ratio of the atoms of each element in a molecule of the compound.
mole ratio of carbon = 60.94/12 = 5.078
mole ratio of hydrogen = 15.36/1 = 15.36
mole ratio of nitrogen = 23.70/14 = 1.693
Now; we will divide by the smallest value
So; carbon = 5.078/1.693 = 2.99 ≅ 3.0
hydrogen = 15.36/1.693 = 9.07 ≅ 9.0
nitrogen = 1.693/1.693 = 1 ≅ 1
Thus, the empirical formula is = C₃H₉N