Moles
A compound has an empirical formula of HCO2 and a molecular of 90 grams per mole. What is the molecular formula of this compound?
H2C2O4
Which is the formula for the compound that forms when magnesium bonds with phosphorous?
Mg3P2
Which species represents a chemical compound?
NaHCO3
A compound contains 0.5 mole of sodium, 0.5 mole of nitrogen, and 1.0 mole of hydrogen. The empirical formula of the compound is
NaNH2
The gram-formula mass of NO2 is defined as the mass of
One mole of NO2
Which represents both an empirical and a molecular formula?
P2O5
What is the molecular formula of a compound with the empirical formula P2O5 and a gram-molecular mass of 284 grams?
P4O10
The graph shows...After 60 minutes, how many grams of water appear to remain in the salt?
0.00
What is the total number of moles of atoms present in 1 gram formula mass of Pb(C2H3O2)2
15
Which sample of O2 contains a total of 3.01 x 10^23 molecules at STP?
16.0g
The mass in grams of 1.00 mole of CaSO4 x 2H2O is
172g
What is the total number of atoms in 1.0 mole of CO2
18 x 10^23
What is the total mass of oxygen in 1.00 mole of Al2(CrO4)3?
192g
What is the ratio by mass of sulfur to oxygen in SO2?
1:1
The total number of molecules in 34.0g of NH3 is equal to
2.00 x 6.02 x 10^23
What is the total mass of 3.01 x 10^23 atoms of helium gas?
2.00g
What is the total number of atoms contained in 80g of neon?
2.4 x 10^24
The accompanying table shows...What is the percent of water in the original sample?
20%
What is the gram-molecular mass of a compound if 5 moles of the compound has a mass of 100 grams?
20g
What is the total number of atoms presented in CuSO4 x 5H2O
21
Which sample contains a total of 6.0 x 10^23 atoms?
23g Na
What is the gram-formula mass of Fe(NO3)3?
242 g/mol
What mass contains 6.0 x 10^23 atoms?
28g of silicon
What is the total number of moles of sulfur atoms in 1 mole of Fe2(SO4)3
3
Approximately how many atoms are there in 3.0 moles of Al?
3(6.0 x 10^23)
What is the total number of molecules contained in .50 mole of O2 at STP?
3.0 x 10^23
What is the gram formula mass of Ca3(PO4)2
310.g
The gram molecular mass of Ca3(PO4)2 is
310g
The percent by mass nitrogen in NH4NO3 is closest to
35%
The data shown...What is the percent of water in the hydrate?
36%
The percent by mass of water in BaCl x 2H20 is equal to
36/243 x 100
The graph shows...What is the percent of water in the original sample?
40%
What is the percent by mass of oxygen in magnesium oxide, MgO?
40%
What is the total mass in grams of 0.75 mole of SO2
48g
The percent by mass of oxygen in CO is approximately
57%
How many moles of hydrogen atoms are present in one mole of C2H4(OH)2
6
What is the total number of molecules of SO2 in a 0.10-mole sample of SO2?
6.0 x 10^22
What is the approximate total number of atoms in 1.0 mole of lithium?
6.0 x 10^23
What is the total number of molecules in 1.0 mole of Cl2(g)
6.0 x 10^23
The gram atomic mass of oxygen is 16.0 grams per mole. How many atoms of oxygen does this mass represent?
6.02 x 10^23
What is the percent composition by mass of hydrogen in NH4HCO3
6.3%
What is the percent by mass of hydrogen in CH3COOH
6.7%
What is the percent by mass of water in the hydrate Na2CO3 x 10H20
62.9%
What is the total number of hydrogen atoms required to form 1 molecule of C3H5(OH)3
8
What is the total number of moles of hydrogen atoms contained in 1 mole of (NH4)2C2O4?
8
A 1.0-mole sample of krypton gas has a mass of
84g
How many oxygen molecules are in 3.36 of gas at STP?
9.03 x 10^22
The gram-formula mass of (NH4)2CO3 is
96.0g
Given the structural formula...What is the empirical formula of this compound?
C2H5O
What is the molecular formula of a compound that has a molecular mass of 42 and an empirical formula of CH2?
C3H6
The gram molecular mass of CO2 is the same as the gram molecular mass of
C3H8
A compound has a molecular mass of 54 and an empirical formula of C2H3. What is the molecular formula of the compound?
C4H6
Which is an empirical formula?
CH
The molecular mass of a compound of carbon and hydrogen is 42. It's empirical formula is
CH2
What is the empirical formula of a compound if a sample contains 8.52 grams of carbon and 1.42 grams of hydrogen?
CH2
Which pair of formulas represents the empirical formula and the molecular formula of a compound?
CH2, C3H6
What is the empirical formula of the compound whose molecular formula is C6H12O6?
CH2O
A compound contains 40% calcium, 12% carbon, and 48% oxygen by mass. What is the empirical formula of this compound?
CaCO3
Which quantity is equivalent to 39 grams of LiF
1.5 moles
Which sample contains a total of 9.0 x 10^23 atoms
1.5 moles of Cu
How many molecules are in 0.25 mole of CO?
1.5 x 10^23
What is the number of moles of N2(g) that contains 9.03 x 10^23
1.50
What is the total number of moles of atoms represented by one mole of (CH3)2NH
10
How many moles of hydrogen atoms are there in one mole of C6H12O6 molecules?
12
The percent by mass of carbon in CO2(g) is equal to
12/44 x 100
The percent composition by mass of nitrogen in NH4OH (gram-formula mass = 35 grams/mole) is equal to
14/35 x 100
The sum of the atomic masses of the atoms in one molecule of C3H6Br2 is called the
Formula mass
In which compound is the percent composition by mass of chlorine equal to 42%?
HClO3
Which substance has the greatest molecular mass
I2
Atom X is in group IIA and atom Y is in group VIIA. A compound formed between these two elements would have the formula?
XY2
