Answer:
Explanation:
When performing a multiplication or division calculation, significant figures in the calculated result are dictated by the significant figures of the measured numbers. The calculated result should have the same significant figure as the measured number in the calculation with the fewest significant figures.
According to the rule guiding significant figures during mathematical operations; when performing multiplications or divisions involving multiple numbers, the final answer should have the same significant figures as the number with the least significant figures.
For example: if 10.54 and 101.25 are multiplied, the final answer should have the same significant figure as 10.54 because this is the number with the least significant figure among the numbers involved in the entire operation.
10.54 has 4 significant figures while 101.25 has 5 significant figures. The final answer should, therefore, have 4 significant figures.
Thus; 10.54 x 101.25 = 1,067
It is desirable to remove calcium ion from hard water to prevent the formation of precipitates known as boiler scale that reduce heating efficiency. The calcium ion is reacted with sodium phosphate to form solid calcium phosphate, which is easier to remove than boiler scale. What volume (in liters) of 0.478 M sodium phosphate is needed to react completely with 0.225 liter of 0.279 M calcium chloride
Answer:
0.0876L of 0.478M Na₃PO₄ are needed
Explanation:
The reaction of calcium chloride, CaCl₂, with sodium phosphate, Na₃PO₄ is:
3CaCl₂ + 2Na₃PO₄ → Ca₃(PO₄)₂ + 6NaCl
Where 3 moles of calcium chloride react with 2 moles of sodium phosphate to produce 1 mole of calcium phosphate.
To solve this question we need to find moles of CaCl₂ added. Using the reaction we can find the moles of Na₃PO₄ that are needed to react completely and the volume using its concentration:
Moles CaCl₂:
0.225L * (0.279mol / L) = 0.0628moles of CaCl₂
Moles Na₃PO₄:
0.0628moles of CaCl₂ * (2mol Na₃PO₄ / 3 mol CaCl₂) =
0.0419moles of Na₃PO₄
Volume 0.478M Na₃PO₄:
0.0419moles of Na₃PO₄ * (1L / 0.478mol) =
0.0876L of 0.478M Na₃PO₄ are neededRe-order each list in the table below, if necessary, so that the atoms or ions in it are listed in order of decreasing size.
atoms or lons:
•Be, Be^+, Li
•Br, I, Cl
•Cl, Na, S
atoms or lons in order
of decreasing size
Answer: Na, S, Cl
Explanation:
Atomic size decreases as one moves from left to right on the periodic table with elements in the same period. This is as a result of the electrons increasing in the outer circle and thus being drawn to the protons in the nucleus which will lead to the outer shell area decreasing.
Sodium (Na) comes before Sulfur (S) which comes before Chlorine (S) so this is the decreasing order as they are all in the same period.
How many mols in 2.25x10^25 atoms of Zinc
Answer:
37.4 mol.
Explanation:
Hello!
In this case, since the Avogadro's number help us to realize that one mole of any substance contains 6.022x10²³ formula units, in this case atoms of zinc, the following dimensional analysis provides the correct answer:
[tex]=2.25x10^{25} atoms*\frac{1mol}{6.022x10^{23}atoms}\\\\= 37.4mol[/tex]
Best regards!
7.00 of Compound x with molecular formula C3H4 are burned in a constant-pressure calorimeter containing 35.00kg of water at 25c. The temperature of the water is observed to rise by 2.316c. (You may assume all the heat released by the reaction is absorbed by the water, and none by the calorimeter itself.) Calculate the standard heat of formation of Compound x at 25c.
Be sure your answer has a unit symbol, if necessary, and round it to 3 significant digits.
Answer:
[tex]\Delta H_{f,C_3H_4}=276.8kJ/mol[/tex]
Explanation:
Hello!
In this case, since the equation we use to model the heat exchange into the calorimeter and compute the heat of reaction is:
[tex]\Delta H_{rxn} =- m_wC_w\Delta T[/tex]
We plug in the mass of water, temperature change and specific heat to obtain:
[tex]\Delta H_{rxn} =- (35000g)(4.184\frac{J}{g\°C} )(2.316\°C)\\\\\Delta H_{rxn}=-339.16kJ[/tex]
Now, this enthalpy of reaction corresponds to the combustion of propyne:
[tex]C_3H_4+4O_2\rightarrow 3CO_2+2H_2O[/tex]
Whose enthalpy change involves the enthalpies of formation of propyne, carbon dioxide and water, considering that of propyne is the target:
[tex]\Delta H_{rxn}=3\Delta H_{f,CO_2}+2\Delta H_{f,H_2O}-\Delta H_{f,C_3H_4}[/tex]
However, the enthalpy of reaction should be expressed in kJ per moles of C3H4, so we divide by the appropriate moles in 7.00 g of this compound:
[tex]\Delta H_{rxn} =-339.16kJ*\frac{1}{7.00g}*\frac{40.06g}{1mol}=-1940.9kJ/mol[/tex]
Now, we solve for the enthalpy of formation of C3H4 as shown below:
[tex]\Delta H_{f,C_3H_4}=3\Delta H_{f,CO_2}+2\Delta H_{f,H_2O}-\Delta H_{rxn}[/tex]
So we plug in to obtain (enthalpies of formation of CO2 and H2O are found on NIST data base):
[tex]\Delta H_{f,C_3H_4}=3(-393.5kJ/mol)+2(-241.8kJ/mol)-(-1940.9kJ/mol)\\\\\Delta H_{f,C_3H_4}=276.8kJ/mol[/tex]
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A treatment plant uses a CMFR as the reactor for the removal of manganese via an oxidation reaction by the addition of potassium permanganate. If the influent manganese concentration is 0.86 mg/L, the plant has a treatment capacity of 3,800 m3/d, the reactor has a volume of 45 m3, and manganese reacts with potassium permanganate in a first order reaction with a reaction rate constant of 0.0125 s-1, what is the effluent concentration
Answer:
the effluent concentration is 0.06236 mg/L
Explanation:
Given that;
treatment capacity [tex]V_{0}[/tex] = 3,800 m³/d = ( 3,800 × 86.4) = 43.98 L/sec
reactor's volume V = 45 m³ = (45 × 1000) = 45,000 L
reaction rate constant K = 0.0125 s⁻¹
influent manganese concentration [tex]CA_{0}[/tex] = 0.86 mg/L
-[tex]r_{A}[/tex] = [tex]KC_{A}[/tex]
Now, performance equation for CSTR is expressed as follows;
[tex]\frac{V}{V_{0} }[/tex] = [tex]\frac{CA_{0} -CA _{} }{-r_{A} }[/tex]
[tex]\frac{V}{V_{0} }[/tex] = [tex]\frac{CA_{0} -CA _{} }{KC_{A} }[/tex]
So we substitute
45000L / 43.98 L/sec = ( 0.86 mg/L - CA) / 0.0125 CA
we cross multiply
562.5CA = 37.8228 - 43.98CA
562.5CA + 43.98CA = 37.8228
606.48CA = 37.8228
CA = 37.8228 / 606.48
CA = 0.06236 mg/L
Therefore, the effluent concentration is 0.06236 mg/L
Explain the differences between an ideal gas and a real gas.
Answer:
Ideal Gas
The ideal gas is extremely small and the mass is almost zero and no volume Ideal gas is also considered as a point mass.
Real Gas
The molecules of real gas occupy space though they are small particles and also have volume.
anation:
The differences between an ideal gas and a real gas are that the ideal gas follows the gas laws perfectly under all conditions. Whereas a real gas deviates from ideal gas behaviors.
The ideal gas law, also known as the general gas equation, is a fundamental principle in thermodynamics and relates the pressure, volume, temperature, and number of moles of an ideal gas.
An ideal gas is a theoretical gas that follows the gas laws perfectly under all conditions of temperature and pressure. It is assumed to have no volume, no intermolecular forces, and elastic collisions between its particles. An ideal gas also obeys the ideal gas law.
On the other hand, a real gas is a gas that does not follow the gas laws perfectly under all conditions of temperature and pressure. Real gases have volume and intermolecular forces that affect their behavior. These forces cause deviations from ideal gas behavior, especially at high pressures and low temperatures.
In summary, while an ideal gas is a theoretical gas that follows the gas laws perfectly under all conditions, a real gas is a gas that deviates from ideal gas behavior due to its volume, intermolecular forces, and non-elastic collisions between its particles.
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Consider the addition of an electron to the following atoms from the fifth period. Rank the atoms in order from the most negative to the least negative electron affinity values based on their electron configurations.
Atom or ion Electron configuration
I [Kr]4d105s25p5
Sn [Kr]4d105s25p2
Xe [Kr]4d105s25p6
Rank the electron affinity from most negative to least negative. To rank items as equivalent, overlap them.
Answer:
I>Sn>Xe
Explanation:
Electron affinity refers to the ability of an atom to accept electron(s) and form a negative ion.
We know that electron affinity is a periodic trend that increases across the period but decreases down the group.
Hence the, electron affinity of iodine is far higher than that of tin. However, xenon is a noble gas and does not accept electrons. Hence, it has an electron affinity of 0 KJ/mol.
A rock's mass is a:
A. all of the above
B. chemical property
C. physical property
D. constant property
Answer:
all of the above
Explanation:
now I will bless you with this-
how is the name of the second element in a covalent molecule changed
Answer:
See explanation
Explanation:
Here we are trying to see how a binary covalent compound is named. A binary covalent compound comprises of only two elements held together by covalent bonds.
The first element retains its normal name whereas the second element has the suffix -ide added to it.
For instance, CO2 is named as carbon dioxide, HBr is named as hydrogen bromide etc.
Answer: it's ide
Explanation:
Got it right in the quiz
The concentration of urea in a solution prepared by dissolving 16 g of urea in 20 g of H2OH2O is ________% by mass. The molar mass of urea is 60.0 g/mol. The concentration of urea in a solution prepared by dissolving 16 g of urea in 20 g of is ________% by mass. The molar mass of urea is 60.0 g/mol. 44 80 0.80 0.48 0.44
Answer:
44
Explanation:
Given that :
Mass of solute = Mass of urea = 16g
Mass of water = 20g
Mass of solution = (mass of solute + mass of solvent) = (mass of urea + mass of water) = (16g + 20g) = 36g
Percentage Mass = (mass of solute / mass of solution) * 100%
Percentage Mass = (16 / 36) * 100%
Percentage Mass = 0.4444444 x 100%
Percentage Mass = 44.44%
Percentage Mass = 44%
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A catalyst decreases the activation energy of a particular exothermic reaction by 56 kJ/mol, to 35 kJ/mol. Assuming that the mechanism has only one step, and that the products are 78 kJ lower in energy than the reactants, sketch approximate energy-level diagrams for the catalyzed and uncatalyzed reactions. What is the activation energy for the uncatalyzed reverse reaction
Answer:
Activation energy for the uncatalyzed reverse reaction = 103 kJ/mol
Explanation:
Activation energy decreases from = 56 kj/mol to 35 kj/mol
products = 78 KJ lower in energy than reactants
Activation energy for the uncatalyzed reverse reaction = 103 kJ/mol
attached below are the sketches of approximate energy-level for both catalyzed and uncatalyzed reactions
Give the structure that corresponds to the following molecular formula and H1 NMR spectrum: The proton N M R shows a triplet at 0.9 p p m integrating to 11238 and a quartet at 1.4 integrating to 7473. THere is a singlet at 1.35 p p m integrating to 1275 that disappears after a D 2 O shake. The unknown compound has a molecular formula of C 7 H 16 O. The magenta numbers in the spectrum are the relative integrals in arbitrary units. Draw the structure.
Answer:
Kindly check the attached picture for the diagram of the chemical compound.
Explanation:
So, the following parameters were given from the question above;
=> A triplet at 0.9 ppm and a quartet at 1.4 ppm, a singlet at 1.35 ppm. Now, the unknown compound has a molecular formula of C7H16O.
For a triplet at 0.9ppm, there are nine (9) atoms of hydrogen, for the quartet at 1.4ppm there are six(6) atoms of hydrogen and for the singlet at 1.35 ppm, the number of hydrogen atoms is one(1). Hence, the total number of hydrogen atoms = 16.
Therefore, number of bondings = [(2 × number of carbon atoms) + 2 - number of hydrogen atoms present on the compound)/2 .
Thus number of bonds =[( 2× 7) + 2 - 16] ÷ 2 = 0.
Hence, there is no double bond or ring in the compound.
Where and in what features is water found on Earth?
Answer: On Earth, liquid water exists on the surface in the form of oceans, lakes and rivers. It also exists below ground as groundwater, in wells and aquifers. Water vapor is most visible as clouds and fog. The frozen part of Earth's hydrosphere is made of ice: glaciers, ice caps and icebergs.
A state of matter where the particles that make up a substance start to break apart
Answer:
Liquid
Explanation:
An average reaction rate is calculated as the change in the concentration of reactants or products over a period of time in the course of the reaction. An instantaneous reaction rate is the rate at a particular moment in the reaction and is usually determined graphically, but it can also be calculated using calculus. The reaction of compound A forming compound B was studied and the following data were collected:
Time (s) [A] (M)
0. 0.184
200. 0.129
500. 0.069
800. 0.031
1200. 0.019
1500. 0.016
Required:
a. What is the average reaction rate between 0 and 1500s?
b. What is the average reaction rate between 200. and 1200s ?
c. What is the instantaneous rate of the reaction at t=800s?
Answer:
Explanation:
a )
Average reaction rate between 0 and 1500s
Time duration = 1500 s
moles reacted = .184 - .016 = .168 moles
Moles reacted per second = .168 / 1500
= 112 x 10⁻⁶ moles /s
b )
Average reaction rate between 200 and 1200s
Time duration = 1000 s
moles reacted = .129 - .019 = .11 moles
Moles reacted per second = .11 / 1000
= 110 x 10⁻⁶ moles /s
c )
the instantaneous rate of the reaction at t=800s
We shall assume that between 500 s and 1200 s , rate of reaction is uniform
rate between 500 and 1200
Time duration = 700 s
moles consumed = .069 - .019 = .05 moles
Rate of reaction = .05 / 700
= 71 .4 x 10⁻⁶ moles / s
This will also be instantaneous rate of reaction at t = 800 s .
A 5.5 gg sample of a substance contains only carbon and oxygen. Carbon makes up 35%% of the mass of the substance. The rest is made of oxygen. You are asked to determine the mass of oxygen in the sample. Which of the following expressions demonstrates a mathematical procedure to solve this problem using the proper order of operations?
a. ((100 - 35)/100) times 5.5 grams =
b. 100 - 35/100 times 5.5 grams =
c. 100 - (35/100) times 5.5 grams=
Answer:
a. ((100 - 35)/100) times 5.5 grams = 3.575 g
Explanation:
Given that:
The sample of carbon and oxygen = 5.5g
where carbon makes 35% of the mass of the substances.
It implies that oxygen will make: (100 - 35)% = 65%
Suppose y be the mass of the oxygen;
Then:
[tex]y = \dfrac{(100-35)}{100} \times 5.5 \ g[/tex]
[tex]y = \dfrac{(65)} {100} \times 5.5 \ g[/tex]
[tex]y = 3.575 \ g[/tex]
The mass of carbon [tex]= \dfrac{35}{100} \times 5.5 \ g[/tex]
= 1.925 g
what is the difference between test tube and boiling tube
Test tubes heat small amounts of liquids while boiling tube boils liquids
show work!!
A sample is 54.7g CaCl2 and 53.64 g H20. How
many water molecules are associated with this
hydrate?
The molecular formula of hydrate : CaCl₂.6 H₂O
So there are 6 molecules of H₂O
Further explanationGiven
54.7g CaCl₂ and 53.64 g H₂O
Required
The number of molecules H₂O
Solution
mol CaCl₂ :
= mass : MW
= 54.7 : 111 g/mol
= 0.493
mol H₂O :
= 53.64 : 18 g/mol
= 2.98
mol ratio H₂O : CaCl₂ :
= 2.98/0.493 : 0.493/0.493
= 6 : 1
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Answer:
no way
Explanation:
more free points
What is the mass of 1.75 moles of Ca(H2C302)2?
Explanation:
first we have to find molar mass of ca(H2c3o2)2
40+(1*2)2+(12*3)2+(16*2)2
40+4+72+64=180g/mole
m=n*Mm
m=1.75mole*180g/mole
m=315g
What is the oxidation number of calcium
Answer:
0 for the elemental form, +2 in its compounds.
To solve the ultraviolet catastrophe, Planck applied quantization to: Select the correct answer below:
A. vibrational energies of atoms
B. orbital energies of electrons
C. kinetic energies of photons
D. temperature of the system
Answer:
Vibrational energies of atoms
Explanation:
Planck applied quantization to Vibrational energies of atoms because in Black body spectrum prediction a blackbody at equilibrium is expected to radiate energies at various Frequencies ( i.e. increase in radiated energy ∝ increase in frequency ) but towards the ultraviolet region of the spectrum the energy radiated begins to drop as frequency increases. The phenomenon of drop in energy with increase in frequency is termed Ultraviolet catastrophe. hence to solve this phenomenon Planck applied quantization to Vibrational energies of atoms
After a big game, you put your water bottle inside the refrigerator. The next
day you see that your water bottle has become dented. Which statement
best describes what happened?
A.
Heat molecules left the water bottle.
B.
Some air molecules were broken down.
C.
The air particles slowed down and got closer together.
D.
Some of the air molecules escaped the water bottle.
Mostly and for what I would say is A
The gases can undergo compression when subjected to lower temperatures and pressure. The water bottle becomes dented as the collision slowed down and got closer to each other. Thus, option C is correct.
What is freezing?Freezing has been the physical process that is involved in changing the states of matter from liquid to solids. This results in a decrease in the entropy of the water which decreases the heat and randomness of the particles.
As the temperature decreases the collision and the kinetic energy of the particles decreases. This results in the loss of entropy and makes the molecules or the particles show a higher force of attraction leading to close packing. The space becomes dense and tightly packed.
As the particle becomes closely packed it dents the water bottle at low temperature as now it has its own shape (solids) unlike the liquids. The lower temperature converts the liquids into solids.
Therefore, as the water freezes the bottle experiences a dent as ice is formed from liquids by freezing.
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Helium on the Moon was found to be 0.420% 2He, 2.75% 3He, and 96.83% 4He. What is the average atomic mass of helium on the Moon?
Answer:
Average atomic mass = 3.9 amu
Explanation:
Given data:
Percent abundance of He-2 = 0.420%
Percent abundance of He-3 = 2.75%
Percent abundance of He-4 = 96.83%
Average atomic mass = ?
Solution:
Average atomic mass = (abundance of 1st isotope × its atomic mass) +(abundance of 2nd isotope × its atomic mass) + (abundance of 3rd isotope × its atomic mass) / 100
Average atomic mass = (0.420×2)+(2.75×3) +(96.83×4)/100
Average atomic mass = 0.84 + 8.25 +387.32 / 100
Average atomic mass = 396.41 / 100
Average atomic mass = 3.9 amu.
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Take Notes...
Change It Up...
Take A Study Nap...
Record What You're Memorizing. ...
Write Everything Down. ...
Section Your Notes. ...
Use the Memory Palace Technique. ...
Apply Repetition to Cumulative Memorization. ...
Teach It to Someone. ...
Listen to the Recordings Continuously....
The balanced equation for the production of sugars by photosynthesis is shown below.
This equation demonstrates the law of conservation of mass because
A.
there are more oxygen atoms on the right side of the equation than on the left.
B.
there is the same number of compounds on the right side of the equation as the left.
C.
there is the same number of each type of atom on the right side of the equation as the left.
D.
the sugar molecule on the right has the same mass as the carbon dioxide molecules on the left.
Answer:
Black
Explanation:
Answer:
the answer is
-there is the same number of each type of atom on the right side of the equation as the left.
Explanation:
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In the reaction 2 HgO --> 2 Hg + O2
how many moles of O2 are produced when 5 moles of HgO are decomposed?
Answer:
2.5 moles of oxygen are produced.
Explanation:
Given data:
Number of moles of O₂ produced = ?
Number of moles of HgO decomposed = 5 mol
Solution:
Chemical equation:
2HgO → 2Hg + O₂
now we will compare the moles of HgO and O₂.
HgO : O₂
2 : 1
5 : 1/2×5 = 2.5
Thus, from 5 moles of HgO 2.5 moles of oxygen are produced.
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Answer:
Six Steps to Control Workplace Hazards
Step 1: Design or re-organise to eliminate hazards. ...
Step 2: Substitute the hazard with something safer. ...
Step 3: Isolate the hazard from people. ...
Step 4: Use engineering controls. ...
Step 5: Use administrative controls. ...
Step 6: Use Personal Protective Equipment (PPE)
Explanation:
i it true?
Why are the non-living things important to an ecosystem?
Answer:
well just like grass that helps animals eat rocks may give an animal a home