Chemistry Exam 1
2. If copper has two naturally occurring isotopes, 63Cu (62.9396 amu) with an abundance of 69.50% and 65Cu (64.9278 amu) with an abundance of 30.50%.
What is the average atomic mass of copper ?
3. In the pair of atoms, 60Co and 60Ni, both atoms have the same
4. What is the correct atomic representation for a species with 10 e-, 8 protons and 10 neutrons?
5. What is the formula of a neutral compound of aluminum and sulfide ions?
a. AlS2
b. AlS3
c. Al2S
d. Al2S3
e. Al3S2
6. Which ion is NOT correctly named?
a. ammonium ion |
NH4+ |
b. carbonate ion |
CO32- |
c. cyanide ion |
CN- |
d. nitrite ion |
NO2- |
e. sulfate ion |
SO32- |
7. Which property is characteristic of metalloids ?
8. A student heats 1.00 g of a blue compound and obtains 0.64 g of a white compound and some colorless gas in a complete reaction. How many grams of the gas are formed ?
9. How many moles of Pt(NH3)2Cl2, a cancer drug, are in 136.5 g of Pt(NH3)2Cl2 ?
10. Sulfur consists of rings consisting of 8 sulfur atoms. What is the best classification for sulfur?
11. How many oxygen atoms are found in 0.40 moles of NaHCO3 ?
12. What is the empirical formula of a compound which contains 36.86% N and 63.14% O ?
13. What is the sum of the coefficients when the chemical equation below is balanced?
__
Bi2O3(s) + __ C(s) __ Bi(s) + __ CO(g)
14. The term "carbohydrate" once meant a compound with the empirical formula of CH2O. What is the molecular formula of ribose, a carbohydrate, which has a molecular weight of 150.13 g/mol.
15. How many moles of O2 are needed to react with 304.5 g of CS2 in the combustion reaction below?
CS2(l) + 3 O2(g) CO2(g) + 2 SO2(g)
16. How many grams of H2O will form when 10.0 g of NH3 mixes with 10.0 g of O2 according to the reaction below ?
4 NH3(g) + 5 O2(g) 4 NO(g) + 6 H2O(l)
17. Which statement(s) below are TRUE?
18. BONUS: When 56.6 g of Ca and 30.5 g of N2 react, only 90.0% of the product is recovered. What mass of Ca3N2 is recovered from this reaction ?
3 Ca(s) + N2(g) Ca3N2(s)