Test Review: The Mole

Non-Calculator Practice All of the problems can be solved with simple operations. Addition Subtraction Multiplication Division Ratios Round when needed.

What is the molar mass of calcium oxide (in two significant figures)? CaO 56 g/mol

About how many moles of calcium oxide are in 280g? CaO 56 g/mol 5.0 moles CaO

How many calcium ions are in 1 mole of calcium oxide? CaO 1mole CaO = 1 mole Ca+2 ions 6.022x1023 Ca+2 ions

What is the molar mass of sulfur tetraoxide (in two significant figures)? 96 g/mol

Approximately what percentage of the mass of sulfur tetraoxide is sulfur (in two significant figures)? SO4 96 g/mol 33%

How many atoms of oxygen would be in 125 molecules of SO4? 1 mole SO4 = 4 atoms of oxygen 500. or 5.00x102 atoms O

A compound is 94% sulfur and 6% hydrogen by mass A compound is 94% sulfur and 6% hydrogen by mass. What is its empirical formula? *remember the rhyme H2S

What is that compound’s molecular formula given its molar mass of 102 g/mol? H2S 102/34 = 3 H6S3

What is the molar mass of lithium chloride? LiCl 42 g/mol

What is the molar mass of ammonium hydroxide? NH4(OH) 35.06 g/mol

Calculate the mass of 0.75 moles of sulfur 24 g Sulfur

What percent of zinc nitrate is oxygen? Zn(NO3)2 50.7 %

How many atoms are in 1. 25 moles of dysprosium (Dy). A. 6 How many atoms are in 1.25 moles of dysprosium (Dy)? A. 6.02 E 23 atoms C. 5.02 E 23 atoms B. 7.53 E 23 atoms D. 1.02 E 24 atoms B. 7.53 x1023 atoms Dy

Approximately what is the percentage of carbon in propane. A. 55%. C Approximately what is the percentage of carbon in propane? A. 55% C. 80% B. 60% D. 70% C3H8 C. 81.7%

What is the empirical formula for C4H10 ?

What is the empirical formula of compound with the following percent composition: **remember the rhyme** 43.0% Sr 25.5% Cr 31.4% O SrCrO4

The empirical formula for a compound is CH2 and its molar mass is 98 The empirical formula for a compound is CH2 and its molar mass is 98.21 g/mol. What is the compound’s molecular formula? C7H14

The empirical formula for a compound is CHBr and its molar mass is 278 The empirical formula for a compound is CHBr and its molar mass is 278.76 g/mol. What is the compound’s molecular formula? C3H3Br3

Calculator Practice

How many atoms are present in 0.270 g of carbon? Mass-Mole-Particle 1.35 E 22 atoms C

What is the molar mass of strontium chloride? SrCl2 158.53 g/mol

Calculate the mass of 3.50 x1012 molecules of sulfur dioxide Particle-Mole-Mass 3.72 x 10-10 g SO2

What is the mass of 5.12 E 24 molecules of oxygen gas? Particle-Mole-Mass 272 g O2

Calculate the mass of 4.5 E 25 molecules of CH4 Particle-Mole-Mass 1200 g CH4

What is the molar mass of iron (III) chlorite? Fe(ClO2)3 258.21 g/mol

How many grams does 0.500 moles of CuBr weigh? Mole-Mass conversion 31.8 g

What is the mass of 2.4 x 1024 molecules of water? 72 g of H2O

How many oxygen atoms does 5 How many oxygen atoms does 5.60 x 1022 molecules of silicon dioxide contain?    SiO2 2 oxygen atoms: 1 molecule SiO2 1.12 E 23

A hydrate of Na2CO3 has a mass of 4. 31 g before heating A hydrate of Na2CO3 has a mass of 4.31 g before heating. After heating, the mass of the anhydrous compound is found to be 3.22 g. Determine the formula of the hydrate and then write out the name of the hydrate.  Na2CO3 · 2H2O sodium carbonate dihydrate