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Ulleksa [173]
3 years ago
8

What is the mass number of 207Pb ? A: 289 B: 207 C: 125 D: 82

Chemistry
1 answer:
Sergio [31]3 years ago
3 0
207 is the mass number. 82 would be the atomic number
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Consider the second-order reaction:
kirza4 [7]

Answer:

Initial concentration of HI is 5 mol/L.

The concentration of HI after 4.53\times 10^{10} s is 0.00345 mol/L.

Explanation:

2HI(g)\rightarrow H_2(g)+I_2(g)


Rate Law: k[HI]^2


Rate constant of the reaction = k = 6.4\times 10^{-9} L/mol s

Order of the reaction = 2

Initial rate of reaction = R=1.6\times 10^{-7} Mol/L s

Initial concentration of HI =[A_o]

1.6\times 10^{-7} mol/L s=(6.4\times 10^{-9} L/mol s)[HI]^2

[A_o]=5 mol/L

Final concentration of HI after t = [A]

t = 4.53\times 10^{10} s

Integrated rate law for second order kinetics is given by:

\frac{1}{[A]}=kt+\frac{1}{[A_o]}

\frac{1}{[A]}=6.4\times 10^{-9} L/mol s\times 4.53\times 10^{10} s+\frac{1}{[5 mol/L]}

[A]=0.00345 mol/L

The concentration of HI after 4.53\times 10^{10} s is 0.00345 mol/L.

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3 years ago
A battery contains two metals that have different tendencies to attract electrons. If one is lithium with an electron affinity o
Vitek1552 [10]

Answer:

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Explanation:

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Indicate how the gas molecules move between the system and the surroundings based on changes in pressure, temperature, and volum
MrMuchimi

The gas molecules move between the system and the surroundings follow PV=nRT.

<h3>What are molecules?</h3>

The smallest particle of a substance has all of the physical and chemical properties of that substance.

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At constant temperature and pressure the volume of a gas is directly proportional to the number of moles of gas. At constant temperature and volume the pressure of a gas is directly proportional to the number of moles of gas.

Learn more about molecules here:

brainly.com/question/14130817

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8 0
2 years ago
Which is more reactive oxygen or hydrogen? explain why?
mash [69]

Answer:

Explanation:

Which is more reactive hydrogen or oxygen?

Hydrogen is not particularly reactive. For example, just mixing hydrogen and oxygen gas will not cause a reaction at room temperature, but many metal elements oxidize at least on the surface in air. ... It is combustible because oxygen wants electrons and takes them from hydrogen to form water.

6 0
2 years ago
Please help me please
Ludmilka [50]

Answer:

b

Explanation:

i read this once and remember,trust me!

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