Chemistry - Chapter 6
How many moles of Pb are in 4.71 × 1021 Pb atoms?
0.00782
What is the mass of 1.56 × 1021 atoms of magnesium in grams?
0.0630
How many moles of bromine gas are in 37.7 grams?
0.236
How many moles are there in 17.5 grams of sodium?
0.761
How many hydrogen atoms are in 35.0 grams of hydrogen gas?
1.05 × 1025
How many moles are there in 82.5 grams of iron?
1.48
How many atoms are in 1.50 moles of fluorine gas?
1.81 × 1024
If a sample of carbon dioxide contains 3.8 moles of oxygen atoms, how many moles of carbon dioxide are in the sample?
1.9
One mole of boron has a mass of ________ g.
10.811
What is the mass percent of hydrogen in water?
11.2
An iron ore sample is found to be 35.00% Fe by mass. How many grams of ore are needed to obtain of Fe?
1297
A 42.7 gram sample of potassium nitrate contains how many grams of potassium?
16.5
Calculate the molar mass of ammonium carbonate.
96.09 g/mol
Calculate the molar mass of calcium nitrate.
164.10 g/mol
What is the mass of 3.09 × 1024 atoms of sulfur in grams?
165
How many moles of fluorine are in 3.2 moles of xenon hexafluoride?
19.2
An estrogen compound with the empirical formula C12H17O2 has a molecular mass of 386.6 g/mol. What is the value of n necessary to find the molecular formula?
2
One mole of ammonium nitrate contains:
2 moles of nitrogen
How many moles of Cu are in 1.48 × 1025 Cu atoms?
24.6
What is the mass percent of carbon in oxalic acid, H2C2O4?
26.7
How many atoms are in 15.6 grams of silicon?
3.34 × 1023
How many atoms are in 5.80 moles of He?
3.49 × 1024
How many moles of carbon are in 3.5 moles of calcium carbonate?
3.5
How many moles of iron are contained in 1.75 kg of iron?
31.3
One mole of oxygen gas has a mass of ________ g.
32.0
What is the molar mass of aluminum sulfate?
342.2 g/mol
What is the mass in grams of 5.40 moles of lithium?
37.5
What is mass of 0.560 moles of chlorine gas?
39.7
One mole of potassium sulfate contains:
4 moles of oxygen
How many molecules of nitrogen monoxide are in a 22.5 gram sample?
4.51 × 1023
If 3.011 × 1023 molecules have a mass of 20.04 grams, what is the molar mass of this substance?
40.08 g/mol
The mass of one mole of carbon dioxide is ________ g.
44.01
A 500. gram iron ore sample was determined to contain 242 grams of iron. What is the mass percent of iron in the ore?
48.4
What is the value of n when the empirical formula is C3H5 and the molecular mass is 205.4 g/mol?
5
How many molecules of sulfur trioxide are in 78.0 grams?
5.87 × 1023
Bauxite is an ore that contains the element aluminum. If you obtained 108 grams of aluminum from an ore sample that initially weighed 204 grams, what is the mass percent of aluminum in this bauxite ore?
52.9
What is the correct value for Avogadro's number?
6.022 × 1023
A 15.5 gram sample of diphosphorous pentoxide contains how many grams of phosphorous?
6.76
One mole of (NH4)2HPO4 contains how many moles of hydrogen atoms?
9
Which of the following contains 9.02 × 1023 atoms?
9.00 g H2O
What is the mass percent of chlorine in hydrochloric acid?
97.2
A 7.96 gram sample of silver reacts with oxygen to form 8.55 gram of the metal oxide. What is the formula of the oxide?
Ag2O
Which of the following statements about empirical formulas is incorrect?
An empirical formula represents a molecule.
You have 10.0 g each of Na, C, Pb, Cu and Ne. Which contains the largest number of moles?
C
An unknown acid has a molar mass of 60.05 g/mol. Given the following percent composition, what is the molecular formula? 40% C, 6.7% H, 53.3% O
C2H4O2
Vitamin C is known chemically by the name ascorbic acid. Determine the empirical formula of ascorbic acid if it is composed of 40.92% carbon, 4.58% hydrogen, and 54.50% oxygen.
C3H4O3
Which of the following is already in its empirical formula?
C5H12O2
A compound has a molar mass of 180.15 g/mol. Given the following percent composition, calculate the molecular formula:
C6H12O6
Determine the correct empirical formula of a compound containing 26.68% carbon, 2.24% hydrogen, and 71.08% oxygen.
CHO2
A chromium oxide compound contains 104.0 grams of chromium and 48.0 grams of oxygen. What is the most likely empirical formula of this compound?
Cr2O3
An iron chloride compound contains 55.85 grams of iron and 106.5 grams of chlorine. What is the most likely empirical formula for this compound?
FeCl3
Determine the empirical formula of a compound containing 83% potassium and 17.0% oxygen.
K2O
Determine the empirical formula of a compound containing 60.3% magnesium and 39.7% oxygen.
MgO
Which of the following compounds has the highest mass percent of "O"?
MnO2
What is the molecular formula of a compound given the molar mass of the compound is 30.04 gram and the empirical formula is NH?
N2H2
If 2.01 × 1023 atoms of an element from Group IA of the periodic table has a mass of 7.675 grams, this element is most likely
Na
One mole of ammonium nitrite contains:
None of A, B, and C
Which of the following statements about the mole is FALSE?
One mole of water contains 1/2 mole of oxygen atoms.
You have 10.0 g each of Na, C, Pb, Cu and Ne. Which contains the smallest number of moles?
Pb
In comparing a balloon containing 25 grams of helium to a balloon containing 25 grams of neon, which one of the following statements is TRUE?
The helium balloon has more atoms
In comparing 1 mole of carbon atoms to one mole of magnesium atoms, which statement is TRUE?
The mass of 1 mole of magnesium is greater than the mass of 1 mole of carbon.
The chemical formula CH2O can be classified as:
empirical, possibly molecular.
The empirical formula of a compound:
indicates the simplest ratio of atoms in the compound
What is the molecular formula of a compound given the molar mass of the compound is 186.5 grams and the empirical formula is C2H7?
none of the above
What would the empirical formula be for the molecular compound C6H9O4?
none of the above
The simplest formula for hydrogen peroxide is HO. To determine its molecular formula, it is necessary to know
the molar mass of hydrogen peroxide
