Relative Molecular Mass Questions

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Question 1:

A balloon is filled with 1.2 x 1024 atoms of helium gas. How many moles of the gas are in the balloon?

 

Question 2:

How many moles of carbon dioxide are in a tank containing 88 g of carbon dioxide? (Remember that the molecular mass of carbon dioxide is 44.0.)

 

Question 3:

How many moles of oxygen molecules are contained in a 16.0 gram sample of oxygen? How many individual molecules of oxygen are contained in the sample?

 

Question 4:

How many grams of hydrogen gas are contained in a 5.0 mole sample of hydrogen? (Remember that the molecular mass of hydrogen is 2.0.)

 

Question 5:

How many grams of carbon tetrafluoride gas are contained in a 0.10 mole sample of that gas? (The molecular mass of carbon tetrafluoride gas is 88.0.) How many individual molecules of gas are contained in the sample?

 

Question 6:

How many carbon dioxide molecules are there in:

(a) ½ mole of carbon dioxide?

(b) 1/10 mole of carbon dioxide?

Question 7:

If the molecular mass of nitrogen is 28, what would be the mass of

(a) ½ mole of nitrogen gas?

(b) 1/10 mole of nitrogen gas?

 

Question 8:

The Australian Government is currently spending about 20 billion dollars per year (2 x 1011 dollars/year). If spending continues at this rate, how long would it take for the government to spend one mole of dollars?

 

Question 9:

If you could count out 1000 marbles per second (a remarkably fast rate), how long would it take you to count out one mole of marbles?  (Before you begin, estimate the units of time your answer will want to be in.)

 

Question 10:

How many grams of each substance are represented by the following:

(a) 2.0 moles of magnesium oxide (molecular mass - 40.3)?

(b) 0.50 mole of sodium chloride (molecular mass = 58.5)?

(c) 0.10 mole of copper (molecular mass = 63.5)?

(d) 0.02 mole of silver nitrate (molecular mass = 169.9)?

 

Question 11:

How many moles of each substance are present in the following:

(a) 22 grams of carbon dioxide (molecular mass = 44)?

(b) 85.0 grams of ammonia (molecular mass = 17.0)?

(c) 0.64 gram of copper (molecular mass = 63.5)?

 

Question 12:

Calculate the mass in grams of:

(a) 5.00 moles of carbon (molecular mass = 12.0).

(b) 10.0 moles of oxygen molecules.

(c) 7.00 moles of iodine (molecular mass = 254).

(d) 5.00 moles of zinc oxide (molecular mass = 81.4).

(e) 0.200 mole of aluminium oxide (molecular mass = 102).

 

Question 13:

A tank of nitrogen gas (molecular mass = 28) contains 980 grams of that gas.

(a) How many moles of gas is this?

(b) How many molecules of gas is this?

Question 14:

What is the mass of

(a) 1 mole of carbon-12 atoms?

(b) 1 mole of carbon-14 atoms?

(c) 1 mole of randomly selected zinc atoms?

(d) 2 mole of H2SO4?

Question 15:

How many moles of

(a) atoms are in 140g of nitrogen gas 

(meaning pure, elemental nitrogen)? 

(b) molecules are in 140g of nitrogen gas?

(c) molecules are in 44g of CO2?

(d) atoms are in 44g of CO2?

(e) CaBr2 are in 200g?

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