Please check the following.
1. What compound is sodium sulfite?
My answer:Na2SO3
2. Which element is a noble gas?
a. N2
b. Cl2
c. Xe
d. I2
My answer: c
3. Which element is most likely to form a cation with a 2+ charge?
a. S
b. P
c. Be
d. Al
My answer: c
4. Which species contains the smallest number of electrons?
a. F
b. O^2-
c. S^2-
d. Cl
My answer: b
5. Who first measured the charge of an electron?
a. Rutherford
b. Medeleev
c. Millikan
d. Laviosier
e. Thomson
My answer: a
6. Convert 4 micrometer to km.
My answer: 4 x 10^-9 km
7. Which of the following volumes is equal to 40 mL?
a. 40 cm^3
b. 40 dm^3
c. 0.40 L
d. 0.00040 kL
My answer: a
8. A ruby has a mass of 12.04 carats (1 carat= 200 mg). Rubies are made of a crystalline form of Al2O3.
a. What percentage of the mass of the ruby is aluminum?
My answer: 52.9%
b. The density of rubies is 4.02 g/cm^3. What is the volume of the ruby?
My answer: 0.5990 cm^3
9. A common mineral in Earth's crust has the chemical composition 34.55% Mg, 19.96% Si, and 45.49% O by mass. What is its empirical formula?
My answer: Mg2SiO4
10. A mass of mercury occupies 0.950 L. What volume, in liters, would an equal mass of ethanol occupy? The density of mercury is 13.546 g/mL and the density of ethanol is 0.789 g/mL.
My answer: 16.3 L
11. How many Fe(II) ions are there in 20.0g FeSO4?
My answer: 7.93 Fe(II) ions
12. Because of the high heat and low humidity in the summer in the Death Valley, California, a visitor requires about one quart of water for every two miles traveled on foot. Calculate the approximate number of liters required for a person to walk 10.0 km in Death Valley.
1 quart=946.35 mL
1 mile=1.60934 km
My answer: 2.94 L
13. What is the empirical formula for Hg2(NO3)2?
a. Hg2(NO3)2
b. Hg(NO3)2
c. Hg(NO3)
d. Hg4(NO3)4
My answer: c
14. Write the formula for the compound formed between potassium and sulfur.
My answer: K2S
15. Determine the name for TiCO3.
My answer: Titanium(II) Carbonate
16. Determine the name for HClO3.
My answer: Chloric acid
17. What is the molar mass of nitrogen gas?
My answer: 28.0g/mol
18. Which of the following has the least tendency to form an ion?
a. Ca
b. K
c. Kr
d. Se
My answer: c
19. A certain alcohol contains only three elements, carbon, hydrogen, and oxygen. Combustion of a 50.0g sample of alcohol produced 95.50g of CO2 and 58.70g of H2O. What is the empirical formula of the alcohol?
My answer: C2H6O
1. Correct. Sodium sulfite is Na2SO3.
2. Correct. The noble gas is Xe.
3. Incorrect. The element that is most likely to form a cation with a 2+ charge is d. Al (aluminum).
4. Incorrect. The species that contains the smallest number of electrons is a. F (fluorine).
5. Incorrect. The correct answer is c. Millikan. Robert Millikan first measured the charge of an electron.
6. Correct. 4 micrometers is equal to 4 x 10^-9 km.
7. Incorrect. The correct answer is c. 40 mL is equal to 0.040 L.
8. a. Incorrect. The percentage of the mass of the ruby that is aluminum is 52.9%.
b. Incorrect. The volume of the ruby is 2.994 cm^3.
9. Correct. The empirical formula of the common mineral in Earth's crust is Mg2SiO4.
10. Incorrect. The correct answer is 1.88 L.
11. Incorrect. The number of Fe(II) ions in 20.0g FeSO4 is 0.142 mol.
12. Incorrect. The approximate number of liters required for a person to walk 10.0 km in Death Valley is 5.91 L.
13. Incorrect. The correct empirical formula for Hg2(NO3)2 is a. Hg2(NO3)2.
14. Correct. The formula for the compound formed between potassium and sulfur is K2S.
15. Correct. The name for TiCO3 is titanium(II) carbonate.
16. Incorrect. The correct name for HClO3 is chloric acid.
17. Correct. The molar mass of nitrogen gas (N2) is 28.0 g/mol.
18. Incorrect. The element that has the least tendency to form an ion is a. Ca (calcium).
19. Incorrect. The empirical formula of the alcohol is C4H10O.
1. Correct! The compound sodium sulfite is indeed Na2SO3. To determine the compound, you can use the chemical symbols for sodium (Na) and sulfite (SO3), and since sodium has a +1 charge and sulfite has a -2 charge, you need two sodium ions (Na+) to balance the charge with one sulfite ion (SO3-).
2. Correct! The element that is a noble gas is Xe. Noble gases are found in Group 18 (VIII A) of the periodic table and have a full outer shell of electrons, making them stable and nonreactive.
3. Incorrect. The correct answer is d. Aluminum (Al) is most likely to form a cation with a 2+ charge. Cations are ions with a positive charge, and aluminum often loses 3 electrons to achieve a stable ionic configuration.
4. Incorrect. The correct answer is a. Fluorine (F) contains the smallest number of electrons. Fluorine has 9 electrons, while the other options have more. Oxygen (O^2-) has 10 electrons, sulfur (S^2-) has 18 electrons, and chlorine (Cl) has 17 electrons.
5. Incorrect. The correct answer is c. Robert Millikan first measured the charge of an electron through his famous oil-drop experiment. J.J. Thomson discovered the electron, but Millikan determined its charge.
6. Incorrect. To convert micrometers (µm) to kilometers (km), you need to divide by 1 billion (10^9), not multiply. The correct conversion is 4 µm = 4 x 10^-9 km.
7. Correct! The volume equivalent to 40 mL is indeed 40 cm^3. Both milliliters (mL) and cubic centimeters (cm^3) represent volume in the metric system and are equivalent.
8. a. Incorrect. The percentage of the mass of the ruby that is aluminum (Al2O3) is approximately 52.9%. To calculate this, you need to find the molar masses of Al2O3 and Al, and then divide the molar mass of aluminum by the molar mass of Al2O3 and multiply by 100.
b. Incorrect. The correct volume of the ruby, given its mass and density, is 2.999 cm^3. To calculate volume, you divide the mass of the ruby (converted to grams) by its density.
9. Incorrect. The correct empirical formula for the common mineral with the given composition is MgSiO3, not Mg2SiO4. To determine the empirical formula, you need to convert the mass percentages to moles, find the mole ratio, and simplify if needed.
10. Incorrect. The correct volume of ethanol that would occupy an equal mass to mercury is 1.204 L, not 16.3 L. To calculate this, divide the mass of the ethanol (equal to the mass of mercury) by its density.
11. Incorrect. To determine the number of Fe(II) ions in 20.0g FeSO4, you need to calculate the number of moles of FeSO4 and then convert that to moles of Fe(II) ions. The correct answer is 0.124 Fe(II) ions.
12. Incorrect. The approximate number of liters required for a person to walk 10.0 km in Death Valley would be 0.23 L, not 2.94 L. To calculate this, you need to multiply the given information (1 quart per 2 miles and 1 mile per 1.60934 km) and convert quarts to liters.
13. Incorrect. The correct empirical formula for Hg2(NO3)2 is a. The empirical formula represents the simplest whole-number ratio of atoms in a compound.
14. Correct! The compound formed between potassium (K) and sulfur (S) is indeed K2S. To determine the formula, you balance the charges of the ions by using the crisscross method.
15. Incorrect. The correct name for TiCO3 is Titanium(IV) carbonate, not Titanium(II) carbonate. In this case, titanium has a +4 oxidation state, hence "Titanium(IV)" in the name.
16. Incorrect. The correct name for HClO3 is Chloric acid. To name this compound, you identify the ions present and use the appropriate naming conventions.
17. Correct! The molar mass of nitrogen gas (N2) is indeed 28.0 g/mol. To calculate the molar mass, you add up the atomic masses of each element in the molecule.
18. Correct! The element with the least tendency to form an ion is Kr (krypton). Noble gases, like Kr, have full outer energy levels, making them stable and less likely to form ions.
19. Incorrect. The correct empirical formula of the alcohol with the given combustion data is C4H10O, not C2H6O. To determine the empirical formula, you need to find the moles of carbon, hydrogen, and oxygen in the combustion products and simplify the ratio.