chemistry homework’s

Chem 104
NAME______________
Homework #2
Due Tuesday 6 September 2022
1. Determine the correct number of significant figures in each of the following:
a. 3427 m
_________________________
b. 13,001 L
_________________________
c. 0.0024 g
_________________________
d. 42,000,000 mg
_________________________
e. 0.502 kg
_________________________
2. Which number is the smallest?
A) 4.38 x 105
B) 4.38 x 10-4
C) 4.38 x 103
D) 4.38 x 10–2
3. When 0.091558 is correctly rounded to three significant figures the number becomes ___.
A) 0.09
B) 0.0916
C) 916
D) 0.093
4. Which of the following temperatures is the highest?
A) 100°C
B) 100°F
C) 100 K
5. If honey has a density of 1.43 g/mL, what is the mass of 2.25 qt, reported in kilograms?
(1 qt = 946 mL)
6. If a piece of rock that has a volume of 0.85 L and a mass of 678 g, what is the density of
the rock in g/mL?
Chem 104
NAME______________
7. The average direct daily use of water in the United States per person is 3.0 x 105 mL.
This includes water for drinking, cooking, bathing, dishwashing, laundry, flushing toilets,
watering lawns, etc. What is the volume, in gallons, of this amount of water? (1 qt = 946
mL, 4 qt = 1 gal)
8. T/F _____The measurement 0.04607 m has more significant figures than the
measurement 46.07 cm.
9. The water molecules in the image below are best described as being in the ________ state.
(circle one – solid, liquid, gas)
10. List at least three noble gas elements found on a periodic table.
11. The chemical formula C3H6O2 indicates that there are _____ carbon atoms in each
molecule.
A) 1
B) 2
C) 3
D) 6
E) 11
12. The type of element is determined by the number of _____ in an atom.
A) protons
B) electrons
C) neutrons
13. The chemistry of an element is determined by the number of _____ in an atom.
A) protons
B) electrons
C) neutrons
Chem 104
NAME_______________
Homework #5
Due Wednesday 5 October 2022
1. Draw a valid Lewis structure for each molecule.
a. HI
c. C2H6
d. C2H2Cl2
2. Draw a valid Lewis structure for each polyatomic ion.
a. H3O+
b. CN–
3. Name each covalent compound or write the formula that corresponds to each name.
a. SO3 ____________________________________________
b. P2S5 ____________________________________________
c. CBr4 ____________________________________________
d. N2O _____________________________________________
e. Selenium dioxide ___________________________________
f. Phosphorus triiodide ______________________________________
g. Dinitrogen pentoxide ______________________________________
h. Carbon tetrachloride _______________________________________
4. Label the bond formed between fluorine and each of the following elements as nonpolar
(NP), polar (P), or ionic (I). (Need help? see section 4.4 in your on-line book)
a. hydrogen _________________________________________________
b. fluorine _________________________________________________
c. carbon _________________________________________________
d. lithium __________________________________________________
e. sulfur _________________________________________________
5. Explain why CHCl3 is a polar molecule but CCl4 is not.
6. Identify each molecule below as either covalent ( C ) or ionic ( I ). Write the chemical
formula for each molecule named below OR give the name from the chemical formula.
a. Na2O ____________________________________________________
b. Cr2O3 ____________________________________________________
c. Selenium dioxide ___________________________________________
d. SF6 ______________________________________________________
e. Gold (III) nitrate ____________________________________________
f. Fe2S3 _____________________________________________________
g. P2S5 ______________________________________________________
h. Phosphorus triiodide _________________________________________
i. CdS ______________________________________________________
j. BF3 _______________________________________________________