So there is this test I need to study for and they will be based upon these questions. There is no answer guide in the book nor the teacher gives us one for whatever reason. So can you guys help answer these questions? I want to make sure I'm getting the right answers.
1. Element A has 2 isotopes. one has an atomic mass of 120 and constitutes 60% ; the other has an atomic mass of 122 and constitutes 40%. which range below includes the avg atomic mass of element A?
A. Less than 120
B. between 120 and 121
C. between 121 and 122
D. greater than 122
2. Which of the following can be determined from the epirical formula of a compound alone?
A. The true formula of the compound
B. Molecular mass of the compound
C. percentage composition of the compound
D. arrangement of atoms within a molecule of the compound
3. How many ions are in 0.5 mole of NaCl?
A. 1.204 X 10 to the 23rd power
B. 3.011 X 10 to the 23rd power
C. 6.022 X 10 to the 23rd power
D. 9.033 X 10 to the 23rd power
4. Antimony has 2 isotopes. One, amounting to 57.3% of the atoms, has a mass of 120.9 amu. The other, 42.7% of the atoms, has a mass of 122.9 amu. What's the avg atomic mass of antimony?
A. 120.9 amu
B. 121.8 amu
C. 121.9 amu
D. 122.1 amu
5. How many moles of calcium (mass=40.1) are in a serving of milk containing 290mg of calcium?
A. 2.90 X 10 to the -3rd power
B. 7.23 X 10
C. 2.90 mol
D. 7.23 mol
6. A sample of pure helium (4.00 g/mol) contains exactly 6.02 X 10 to the 22nd power particles. Whats the mass of the sample?
A. 0.40g
B. 1g
C. 2g
D. 4g
7. When an electric current is passed through water, hydrogen and oxygen are produced in 2:1 volume ratio and a 1:8 mass ratio. What is the empirical formula of water?
A.HO
B.H2O
C.H2O8
D.HO8
8.How would the experimental result have been different if hydrogen gas existed as individual atoms whereas oxygen formed molecules with 2 atoms bound by a covalent bond?
A.Result would be the same.
B.Volume ratio of hydrogen to oxygen would be 1:1
C.Volume ratio of hydrogen to oxygen would be 1:4
D.Volume ratio of hydrogen to oxygen would be 4:1
9. What's the empirical formula of calcium phosphate (ions: Ca 2+charge and PO4 3- charge)?
A. CaPO4
B. Ca2PO4
C. Ca3PO4
D. Ca3P2O8
10. How many moles of oxygen atoms are there in 100 moles of carbon dioxide?
A. 66.7
B. 72.7
C. 100
D. 200
11. How many grams of carbon are contained in 200g of carbon dioxide?
A. 27.29
B. 42.88
C. 54.58
D. 85.76
1. Element A has 2 isotopes. one has an atomic mass of 120 and constitutes 60% ; the other has an atomic mass of 122 and constitutes 40%. which range below includes the avg atomic mass of element A?
A. Less than 120
B. between 120 and 121
C. between 121 and 122
D. greater than 122
2. Which of the following can be determined from the epirical formula of a compound alone?
A. The true formula of the compound
B. Molecular mass of the compound
C. percentage composition of the compound
D. arrangement of atoms within a molecule of the compound
3. How many ions are in 0.5 mole of NaCl?
A. 1.204 X 10 to the 23rd power
B. 3.011 X 10 to the 23rd power
C. 6.022 X 10 to the 23rd power
D. 9.033 X 10 to the 23rd power
4. Antimony has 2 isotopes. One, amounting to 57.3% of the atoms, has a mass of 120.9 amu. The other, 42.7% of the atoms, has a mass of 122.9 amu. What's the avg atomic mass of antimony?
A. 120.9 amu
B. 121.8 amu
C. 121.9 amu
D. 122.1 amu
5. How many moles of calcium (mass=40.1) are in a serving of milk containing 290mg of calcium?
A. 2.90 X 10 to the -3rd power
B. 7.23 X 10
C. 2.90 mol
D. 7.23 mol
6. A sample of pure helium (4.00 g/mol) contains exactly 6.02 X 10 to the 22nd power particles. Whats the mass of the sample?
A. 0.40g
B. 1g
C. 2g
D. 4g
7. When an electric current is passed through water, hydrogen and oxygen are produced in 2:1 volume ratio and a 1:8 mass ratio. What is the empirical formula of water?
A.HO
B.H2O
C.H2O8
D.HO8
8.How would the experimental result have been different if hydrogen gas existed as individual atoms whereas oxygen formed molecules with 2 atoms bound by a covalent bond?
A.Result would be the same.
B.Volume ratio of hydrogen to oxygen would be 1:1
C.Volume ratio of hydrogen to oxygen would be 1:4
D.Volume ratio of hydrogen to oxygen would be 4:1
9. What's the empirical formula of calcium phosphate (ions: Ca 2+charge and PO4 3- charge)?
A. CaPO4
B. Ca2PO4
C. Ca3PO4
D. Ca3P2O8
10. How many moles of oxygen atoms are there in 100 moles of carbon dioxide?
A. 66.7
B. 72.7
C. 100
D. 200
11. How many grams of carbon are contained in 200g of carbon dioxide?
A. 27.29
B. 42.88
C. 54.58
D. 85.76