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2 years ago

What is the average atomic mass of the element?

Chemistry

1 answer:

morpeh [17]2 years ago

7 0

The average atomic mass of element X is 14.007 u.

The average atomic mass of X is the <em>weighted average</em> of the atomic masses of its isotopes.

We multiply the atomic mass of each isotope by a number representing its <em>relative importance</em> (i.e., its % abundance).

Thus,

0.996 36 × 14.003 u =13.952 03 u

0.003 64 × 15.000 u = <u>0.054 60 u</u>

__________TOTAL = 14.007 u

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The half-life of radon gas is approximately four days. Four weeks after the introduction of radon into a sealed room, the fracti

maksim [4K]

The fraction of the original amount remaining is closest to 1/128

<h3>Determination of the number of half-lives</h3>

Half-life (t½) = 4 days
Time (t) = 4 weeks = 4 × 7 = 28 days
Number of half-lives (n) =?

n = t / t½

n = 28 / 4

n = 7

<h3>How to determine the amount remaining </h3>

Original amount (N₀) = 100 g
Number of half-lives (n) = 7
Amount remaining (N)=?

N = N₀ / 2ⁿ

N = 100 / 2⁷

N = 0.78125 g

<h3>How to determine the fraction remaining </h3>

Original amount (N₀) = 100 g
Amount remaining (N)= 0.78125 g

Fraction remaining =?

Fraction remaining = N / N₀

Fraction remaining = 0.78125 / 100

Fraction remaining = 1/128

Learn more about half life:

brainly.com/question/26374513

7 0

2 years ago

Compare the arrangements of individual particles in solids, liquids, and has

erastovalidia [21]

Solids have particles that stay in place and vibrate (least energy)
Liquids have enough energy to slide past each other and have no definite shape.
Gas has a lot of energy and moves freely with no certain shape or volume

5 0

3 years ago

The vapor pressure of water is 1.00 atm at 373 K, and the enthalpy of vaporization is 40.68 kJ mol!. Estimate the vapor pressure

Yuki888 [10]

Answer:

The vapor pressure at temperature 363 K is 0.6970 atm

The vapor pressure at 383 K is 1.410 atm

Explanation:

To calculate $\Delta H_{vap}$ of the reaction, we use clausius claypron equation, which is:

$\ln(\frac{P_2}{P_1})=\frac{\Delta H_{vap}}{R}[\frac{1}{T_1}-\frac{1}{T_2}]$

where,

$P_1$ = vapor pressure at temperature $T_1$

$P_2$ = vapor pressure at temperature $T_2$

$\Delta H_{vap}$ = Enthalpy of vaporization

R = Gas constant = 8.314 J/mol K

1) $\Delta H_{vap}=40.68 kJ/mol=40680 J/mol$

$T_1$ = initial temperature =363 K

$T_2$ = final temperature =373 K

$P_2=1 atm, P_1=?$

Putting values in above equation, we get:

$\ln(\frac{1 atm}{P_1})=\frac{40680 J/mol}{8.314J/mol.K}[\frac{1}{363}-\frac{1}{373}]$

$P_1=0.69671 atm \approx 0.6970 atm$

The vapor pressure at temperature 363 K is 0.6970 atm

2) $\Delta H_{vap}=40.68 kJ/mol=40680 J/mol$

$T_1$ = initial temperature =373 K

$T_2$ = final temperature =383 K

$P_1=1 atm, P_2?$

Putting values in above equation, we get:

$\ln(\frac{P_2}{1 atm})=\frac{40680 J/mol}{8.314J/mol.K}[\frac{1}{373}-\frac{1}{383}]$

$P_2=1.4084 atm \approx 1.410 atm$

The vapor pressure at 383 K is 1.410 atm

8 0

3 years ago

If 12g nitrogen gas,0.40 of H2 gas and 9.0 gram of oxygen are put into 1 litre container of. 27°C what is the total pressure on

Vadim26 [7]

Answer:

Total pressure = 27.35 atm

Explanation:

Given data:

Mass of nitrogen = 12 g

Mass of H₂ = 0.40 mol

Mass of oxygen = 9.0 g

Volume of Container = 1 L

Temperature = 27 °C (27+273 = 300 K)

Total Pressure = ?

Solution:

First of all we will calculate the number of moles of individual gas.

Number of moles = mass/ molar mass

Number of moles = 12 g/ 28 g/mol

Number of moles = 0.43 mol

Pressure of N₂:

PV = nRT

P = nRT/V

P = 0.43 mol × 0.0821 atm.L/mol.K× 300 K/ 1 L

P = 10.6 atm

Number of moles of Oxygen:

Number of moles = mass/ molar mass

Number of moles = 9 g/ 32 g/mol

Number of moles = 0.28 mol

Pressure of O₂:

PV = nRT

P = nRT/V

P = 0.28 mol × 0.0821 atm.L/mol.K× 300 K/ 1 L

P = 6.9 atm

Pressure of H₂:

PV = nRT

P = nRT/V

P = 0.40 mol × 0.0821 atm.L/mol.K× 300 K/ 1 L

P = 9.85 atm

Total pressure:

Total pressure = Pressure of H₂ + Pressure of O₂ + Pressure of N₂

Total pressure = 9.85 atm + 6.9 atm + 10.6 atm

Total pressure = 27.35 atm

8 0

3 years ago

What is the result of the following calculation? Record to the correct number of significant figures.

andriy [413]

Answer:

8.15103

Explanation:

3 0

2 years ago