Name: ____________________________________

Chemistry Practice: The Mole; Concepts, Calculations and Comparisons

1. Concepts:

a.) ______________ Which SI base unit is used to define the amount of substance?

b.) ______________ What is the mass of 6.02x10²³ molecules of water?

c.) ______________ What is the mass of 1 mole of Mg atoms.

d.) ______________ What volume will 1.0 mol of mercaptin gas occupy at STP?

e.) ______________ How many molecules of SO₂ are in 1.0 mol of SO₂ gas?

f.) ______________ One mole of an element was found to have a mass of 65.4 grams. What is the element?

g.) ______________ How many molecules of hydrogen are contained in 11.2 L of H₂ gas?

h.) ______________ How many atoms of Br are in 1.00 mol of Br₂?

2. Conversions – you must show dimensional analysis calculations below!

a.) What is the mass of 2.50 moles of potassium chloride, KCl?

b.) How many grams of oxygen gas, O₂, are contained in 30.0 L of oxygen gas at STP (std temp & pressure)?

c.) How many molecules of tetraphosphorous decoxide, P₄O₁₀ are in 2.00x10³g of tetraphosphorous decoxide?

d.) What volume at STP will 0.50 mol of ammonia gas, NH₃, have?

e.) 0.0032 grams of nicotine (F.M.= 162 g/mol) are contained in 1 cigarette. How many molecules is this?

f.) What is the mass of 3.88x10²¹ units (molecules) of magnesium nitrate, Mg(NO₃)₂ ?

g.) 3.00g of dry ice (solid carbon dioxide, CO₂) is converted to a gas. How many moles are present of this gas?

What volume would it occupy?

h.) How many molecules are in a 1.86 mol sample of riboflavin?

i.) What is the mass of 3.62 moles of sodium carbonate, Na₂CO₃?

j.) What volume will 325 grams of sulfur dioxide, SO₂, occupy at STP? What is the density of this gas?

Comparisons:

a.) ______________ 1 mole of Ag atoms contains ( more / less / the same number of ) atoms than/as 1 mole of Au.

b.) ______________ 1 mole of H₂O contains (more / less / the same) mass as one mole of UF₆.

c.) ______________ 1 mole of C₆H₁₂O₆ contains (the same number as / more / less ) atoms of C as 1 mol of CO₂?

d.) ______________ 1 mol of H₂ gas occupies (more / less / the same ) volume as 1 mole of SO₂.

e.) ______________ Rank from LEAST to GREATEST amount of Ca atoms:

A.) 0.2 mol Ca B.) 1x10²⁰ Ca atoms C.) 10 g Ca