Homework #1
- Page ID
- 36910
Homework is due in class by the date indicated above. Late homework will be docked significantly.
Q1
Complete each calculation with the correct number of significant figures
- \(\dfrac{7.68 \times 8.009}{4.1}\phantom{\dfrac{\Big(}{\Big(}}\)
- \(\dfrac{6.89-5.452}{1.596+4.7121}\phantom{\dfrac{\Big(}{\Big(}}\)
- \(\dfrac{3.668\times10^{-7}+ 8.3469\times10^{-7}}{3.7348\times10^{-10}}\phantom{\dfrac{\Big(}{\Big(}} \)
Q2
Calculate how many grams of mixture are there if 250 mL of ethanol is mixed with 500 mL of benzene.
Substance | Density (g/cm3) |
Ethanol | 0.789 |
Benzene | 0.880 |
Q3
Give the ISOTOPIC symbol for the following ions:
- Ion with 73 Protons, 75 Electrons, and 107 Neutrons.
- Ion with 28 Protons, 25 Electrons, and 31 Neutrons
- Ion with 37 Protons, 37 Electrons, and 49 Neutrons
- Ion with 7 Protons, 7 Electrons, and 7 Neutrons
Q4
Label the following elements as halogens, alkali metals, alkaline earth metals, noble gases, or transition metals.
- Lithium,
- Chlorine
- Argon
- Krypton
- Calcium
- Barium
- Cesium
- Fluorine
- Radon
- Tungsten
Q5
An element consists of the following isotopes. What is the average atomic mass and the name of the element?
Percent natural abundance | Mass (u) |
90.48% | 19.9924 |
0.27% | 20.9938 |
9.25% | 21.9914 |
Q6
A compound, made only from mercury and sulfur, is 86.2% \(Hg\) by mass. The molar mass of this compound is 465 g/mol. Determine the empirical formula and the molecular formula of this compound.
Q7
A compound is a common first-aid antiseptic. The products of its combustion reaction in the presence of oxygen gas are water and carbon dioxide. This compound is composed of carbon, hydrogen and oxygen. If 9.214 g of this compound produces 17.604 g carbon dioxide and 10.812 g water, what is the empirical formula of this compound? Hint: Some oxygen atoms of the products may come from oxygen gas.
Q8
Assign the oxidation state of each atom for the following compounds.
- \(Al\)
- \(PbSO_4\)
- \(H_2SO_3\)
- \(NaHCO_3\)
- \(H_2O_2\)
- \(Ne\)
- \(MgCO_3\)
- \(Na_2Cr_2O_7\)