Chem ch 6

What is the mass of 4.91×10^21 platinum atoms?

1.59 g

How many formula units make up 18.0 g of magnesium chloride (MgCl2)?

1.14x10^23

How many grams are in 3.80 mol of sodium chloride (NaCl)?

1.35x10^24

How many grams of Cl are in a 38.0-g sample of the chlorofluorocarbon CF3Cl?

12.9 g

How many grams of OO are present in 25 gg MgCO3?

14

Calculate the number of grams of sulfur in 4.75 mol of sulfur.

152.3 g

How many grams of KK are present in 32 gg of K2CO3?

18

How many gold atoms are in a pure gold ring containing 3.83×10−23.83×10−2 mol Au mol ?

2.31x10^22

How many grams of Cl are in a 38.0-g sample of the chlorofluorocarbon C2F3Cl3?

21.6 g

How many grams of Cl are in a 38.0-g sample of the chlorofluorocarbon CF2Cl2?

22.3 g

How many water molecules are in a block of ice containing 2.25 mol of water (H2O)?

222.1

How many moles of KK are present in 12 moles of K2CO3?

24

How many grams of Cl are in a 38.0-g sample of the chlorofluorocarbon CFCl3

29.4g

Determine the mass of oxygen in a 5.8-g sample of sodium bicarbonate (NaHCO3).

3.3g

What is the pseudoformula of ascorbic acid, given that ascorbic acid contains 3.407 mol of carbon, 4.53 mol of hydrogen, and 3.406 mol of oxygen?

3.407C 4.53H, 3.406O

Ascorbic acid (vitamin C) contains 40.92% carbon, 4.58% hydrogen, and 54.50% oxygen by mass. Assume a 100-gg sample of ascorbic acid. How many moles of carbon, hydrogen, and oxygen are present in a 100-g sample of ascorbic acid? Use the periodic table as needed.

3.4=C, 4.5=H, 3.4=O

How many atoms of carbon are contained in 47.6 g of Al2(CO3)3? The molar mass of Al2(CO3)3 is 233.99 g/mol.

3.68x10^23

Determine the mass of oxygen in a 7.20-g sample of Al2(SO4)3.

4.04 g

Determine the number of atoms in a 48.3-g sample of zinc.

4.45x10^23

Acetic acid (HC2H3O2) is the active ingredient in vinegar. Calculate the mass percent composition of O in acetic acid.

52.28%

Determine the mass of iron in 79.2 g of Fe2O3.

55.4 g

Calculate the mass of 1.23×10^24 helium atoms.

8.18 g He

How many aluminum atoms are in 3.78 g of aluminum?

8.44x10^22

Ibuprofen, an aspirin substitute, has a mass percent composition of 75.69% C, 8.80% H, and 15.51% O. Calculate its empirical formula.

C13H18O2

The rotten smell of a decaying animal carcass is partially due to a nitrogen-containing compound called putrescine. Elemental analysis of putrescine indicates that it consists of: 54.50% C, 13.73% H, and 31.77% N. Calculate the empirical formula of putrescine.

C2H6N

What is the empirical formula of ascorbic acid, given that the pseudoformula is C=3.407 H=4.53 O=3.406?

C3H4O3

Ascorbic acid has a molar mass of 176.14 g/mol . What is the molecular formula of ascorbic acid?

C6H8O6

Citric acid, the compound responsible for the sour taste of lemons, has an elemental composition of 37.51% C, 4.20% H, and 58.29% O Calculate the empirical formula of citric acid.

C6H8O7

A laboratory analysis of vanillin, the flavoring agent in vanilla, indicates that its mass percent composition is 63.15% C, 5.30% H, and 31.55% O. Determine the empirical formula of vanillin.

C8H8O3

A 15.35 g sample of an unknown compound is found to contain 6.13 gg C, 1.03 g H, and the remainder is O. What is the empirical formula of the compound?

CH2O

A sample of a compound is found to contain 5.65 g C and 15.05 g O. What is the empirical formula of the compound?

CO2

A sample of an unknown compound is decomposed and found to contain 3.47 g N and 0.75 g H. What is the empirical formula of the compound?

NH3