Scientific Notation
What is 2.0 x 10-4 in standard form?
0.0002
How many moles are equal to 3.5 atoms of carbon?
3.5 atoms x (1mol/6.022x10^23)
5.81 x 10-24 atoms
Determine the molar mass of SiF4
104.09 g/mol
Determine the percent oxygen in H2O
88.79%
What is the empirical formula for a molecule with 74.87% carbon and 25.13% hydrogen?
C: 74.87 g/12.01 g = 6.23/6.23 = 1
H: 25.13 g/1.01 g = 24.88/6.23 = 4
CH4
What is 0.00000030054 in scientific notation?
3.01 x 10-7
How many molecules are in 3.15 mol of NaCl?
3.15 mol x (6.022x1023 molecules/1 mol)
1.9 x 1024
Determine the molar mass of (NH4)2(SO3)
116.16 g/mol
Determine the percent composition of each element in Na2S
Na: 58.92%
S: 41.08%
What is the empirical formula for a compound with oxygen and 52.3% carbon?
C: 52.3 g/12.01 g = 4.35/2.98 = 1.46*2 = 3
O: 47.7 g/16 g = 2.98/2.98 = 1 *2 = 2
C3O2
What is 9320000002 in scientific notation?
9.32 x 109
How many milligrams are equal to 0.00127 pounds?
(1 lb = 16 oz) (1 oz = 28.34 g)
0.00127 lb x (16 oz/1 lb) x (28.34 g/1 oz) x (1000 mg/1 g)
575.87 mg
Determine the molar mass of (Ba(MnO4)2)3 and put in scientific notation
1.13 x 103 g/mol
Determine the percent composition of each element in Cu2(CrO4)
Cu: 52.28%
Cr: 21.39%
O: 26.33%
What is the molecular formula for Mg(ClO3)2 with a molar mass of 378.3 g/mol?
24.31+(2x35.45)+(6x16) = 191.21 g/mol
378.3/191.21 = 1.98 --> 2
2 x Mg(ClO3)2 = Mg2(Cl2O6)4
Solve the following with all work. Put in proper scientific notation.
35,670,000 / 12,340
(3.57x107) / (1.23x104)
(3.57/1.23) (107 /104)
(2.9 x 103)
How many minutes are in 2.73 years?
2.73 yr x (365 days/1 yr) x (24 hr/1 day) x (60 min/1 hr)
1,434,888 min
1.43 x 106 min
How many moles are equal to 345 g of CaO2?
Molar mass: 72.08 g/mol
345 g x (1 mol/72.08 g)
4.79 mol
Determine the percent composition of each element in Zn(NO3)2
Zn: 34.52%
N: 14.79%
O: 50.69%
What is the empirical formula and molecular for a compound that is 83.7% carbon and 16.3% hydrogen, and a molar mass of 212.3 g/mol?
C: 83.7 g/12.01 g = 6.97/6.97 = 1 x 3 = 3
H: 16.3 g/1.01 g = 16.14/6.97 = 2.32 x 3 = 7
C3H7
(3*12.01)+(7*1.01) = 43.1 g/mol
212.3/43.1 = 4.93 --> 5
5 x C3H7 = C15H35
Solve the following with all work. Put in proper scientific notation.
(0.987) (560,000)
(9.87 x 10-1) (5.6 x 105)
(9.87 x 5.6) (10-1 x 105)
(55.27) (104)
5.53 x 105
How many feet is 38.2 km? Write your answer in scientific notation.
(1 in = 2.54 cm)
38.2 km x (100000 cm/1 km) x (1 in/2.54 cm) x (1 ft/12 in)
1.25 x 105 ft
What is the mass of 4.11 mol of HMg(C2H3O2)3
Molar mass: 202.38 g/mol
4.11 mol x (202.38 g/1mol)
831.78 g
Glucose and fructose are isomers, meaning they have the same chemical formula (C6H12O6) but different structures. A reaction between those two sugars forms water and a disaccharide, sucrose. What is the percent composition of each element in sucrose?
Sucrose: C12H22O11
C: 42.1%
H: 6.49%
O: 51.41%
What is the percent composition of each element in the empirical formula for C12H18O6?
Empirical: C2H3O
C: 55.8%
H: 7.03%
O: 37.17%