Which statement is true about elements?

A graduated cylinder (approximate as a regular cylinder) has a radius of 1.045 cm and a height of 30.48 cm. What is the volume o

Stels [109]

Answer: 104.5 cm^3

Explanation:

6 0

3 years ago

The average atomic mass of Eu is 151.96 amu. There are only two naturally occurring isotopes of europium, Eu with a mass of 151.

earnstyle [38]

Answer:

The percentage abundance of Eu isotopes are 52 % and 48 % .

Explanation:

The formula for the calculation of the average atomic mass is:

$Average\ atomic\ mass=(\frac {\%\ of\ the\ first\ isotope}{100}\times {Mass\ of\ the\ first\ isotope})+(\frac {\%\ of\ the\ second\ isotope}{100}\times {Mass\ of\ the\ second\ isotope})$

Given that:

Since the element has only 2 isotopes, so the let the percentage of first be x and the second is 100 -x.

For first isotope,:

% = x %

Mass = 151.0 amu

For second isotope :

% = 100 - x

Mass = 153.0 amu

Given, Average Mass = 151.96 amu

Thus,

$151.96=\frac{x}{100}\times {151.0}+\frac{100-x}{100}\times {153.0}$

Solving for x, we get that:

x = 52 %

Thus percentage abundance of Eu isotopes are 52 % and 48 % .

7 0

2 years ago

Determine which law is appropriate for solving the following problem. Carbon dioxide is in a steel tank at 20°C, 10 liters and 1

patriot [66]

Answer:

Law used: Combined Gas Law

Explanation:

We are given the following problem:

Carbon dioxide is in a steel tank at 20°C, 10 liters and 1 atm. What is the pressure on the gas when the tank is heated to 100°C?

To solve this, the most appropriate law that can be used it Combined Gas Law, which is the result of combining the Boyle's law, Charles' law, and Gay-Lussac's law together.

5 0

3 years ago

Read 2 more answers

How many of the following are found in 15.0 kmol of xylene (C8H10)? (a) kg C8H10; (b) mol C8H10; (c) lb-mole C8H10; (d) mol (g-a

77julia77 [94]

Answer:

a) 1592.4 kg C8H10

b) 15*10³ mol C8H10

c) 33.1 lb-mole

d) 1.2 *10^5 mol C

e) 1.5 * 10^5 mol H

f) 1.44 * 10^6 grams C

g) 1.52 * 10^5 grams H

h) 9.03*10^27 molecules C8H10

Explanation:

Step 1: Data given

Number of moles C8H10 = 15.0 kmol =15000 moles

Molar mass of C8H10 = 106.16 g/mol

Step 2: Calculate mass C8H10

Mass C8H10 = moles C8H10 * molar mass C8H10

Mass C8H10 = 15000 * 106.16 g/mol

Mass C8H10 = 1592400 grams = 1592.4 kg

Step 3: Calculate moles C8H10

15.0 kmol = 15*10³ mol C8H10

Step 4: Calculate lb-mol

15.0 kmol = 33.1 lb-mole

Step 5: Calculate moles of C

For 1 mol C8H10 we have 8 moles of C

For 15*10³ mol C8H10 we have 8* 15*10³ =1.2 *10^5 mol C

Step 6: Calculate moles H

For 1 mol C8H10 we have 10 moles of H

For 15*10³ mol C8H10 we have 10* 15*10³ = 1.5 * 10^5 mol H

Step 7: Calculate mass of C

Mass C = moles C * molar mass C

Mass C = 1.2 *10^5 mol C * 12 g/mol

Mass C = 1.44 * 10^6 grams

Step 8: Calculate mass of H

Mass H = moles H * molar mass H

Mass H = 1.5 *10^5 mol H * 1.01 g/mol

Mass C = 1.52 * 10^5 grams

Step 9: Calculate molecules of C8H10

Number of molecules = number of moles * number of Avogadro

Number of molecules = 15*10³ mol C8H10 * 6.022*10^23

Number of molecules = 9.03*10^27 molecules

8 0

2 years ago

A chemist carefully measures the amount of heat needed to raise the temperature of a 894.0g sample of a pure substance from to −

astraxan [27]

Answer:

C = 0.2349 J/ (g °C)

Explanation:

Mass, m = 894.0g

Initial Temperature = −5.8°C

Final Temperature = 17.5°C

Temperature change = 17.5°C - (−5.8°C) = 23.3

Heat, H = 4.90kJ = 4900 J

Specific heat capacit, C = ?

The relationship between these quantities is given by the equation;

H = mCΔT

C = H / mΔT

C = 4900 / (894)(23.3)

C = 0.2349 J/ (g °C)

4 0

2 years ago