Unit 2 Test--Smallest of the Small

True/False

  1. The calculation below shows a correct way of changing 2 inches into miles:

  2. Xenon is a non-metallic element.

  3. The best name for CaCl2 is calcium dichloride.

  4. The best name for NO is dinitrogen oxide.

  5. The best name for FeSO4 is iron sulfate.

  6. The atomic masses on the periodic table were originally relative to the mass of an iron atom.

  7. Nitrogen gas is an example a molecule formed from two atoms.

  8. Equal volumes of gases at the same temperature and pressure contain the same number of particles.

  9. Cu(NO3)2 has five oxygen atoms.

  10. In the Gross Mass Lab, a student accidently counted partial grains of rice while finding the number of rice grains in a gram-relative mass. This would result in the number of rice grains in a gram-relative mass being too large.

Multiple Choice (Choose the best answer.)

  1. Which of the following compounds is not correctly named?

    SO2, sulfur dioxide

    CO, carbon monoxide

    NO2, dinitrogen oxide

    CCl4, carbon tetrachloride

    SO3, sulfur trioxide

  2. Which of the following molecular weights is not correct? (At. Wts: H = 1, O = 16, S = 32)

    H2O = 18

    H2S = 34

    SO2 = 32

    H2SO4 = 98

    None of these.

  3. What is the molar mass of copper nitrate Cu(NO3)2? (At. Wts: Cu = 63.5, N = 14.0, O = 16.0)

    139.5 g

    171.5 g

    227.2 g

    157.5 g

    187.5 g

  4. What is the mass of .350 mole of silver nitrate (AgNO3)? (At. Wts: Ag = 108, N = 14.0, O = 16.0)

    35.0 g

    76.4 g

    485 g

    59.5 g

    170 g

  5. How many moles of copper are present in 7.50 g of copper? (At. Wt: Cu = 63.5)

    0.118 mol

    63.5 mol

    0.130 mol

    476 mol

    7.5 mol

  6. Which of the following quantities represents the greatest mass of nitrogen gas (N2)?

    22.4 moles

    1 liter

    28.0 g

    6 x 10 23 molecules

    More than one of these answers is correct.

  7. One mole of carbon tetra bromide has all the following properties but one. Identify the exception.

    It contains 5 moles of atoms.

    Together all the atoms weigh 332 g.

    It contains 4 bromine atoms.

    It contains 6.02 x 10 23 carbon atoms.

    The total mass of the carbon atoms is 12 grams.

  8. What could be the molecular formula for octane, given that its empirical formula is C4H9?

    C4H9

    C8H18

    C12H27

    C16H36

    Any of these is OK.

  9. Diethyl ether, a substance commonly used as an anesthetic, has the formula C2H5OC2H5. According to this formula, which one of the following statements concerning diethyl ether is false?

    Diethyl ether is a substance made up of 5 elements.

    Each molecule of diethyl ether is made up of 15 atoms.

    One mole of diethyl ether contains 4 moles of C atoms in addition to other elements.

    Diethyl ether is a compound, not an element.

    The structural formula of diethyl ether could be:

  10. A student wanted to convert 10 inches to meters using the calculation at right. What, if anything, is wrong with the calculation?

    the units don't cancel correctly

    2.54 cm doesn't equal 1 inch

    100 m doesn't equal 1 cm-- 100 cm = 1 m

    all the fractions are inverted

    the calculation is correct

Problem Solving (Show All Work. Use Correct Units And Significant Figures.)

1) What is the mass of a single molecule of carbon dioxide? (At. Wts: C = 12, O = 16)

2) How many water molecules are in a cup of water? One cup of water 250 g. (At. Wts: H = 1, O = 16)

3) Quantitative analysis of 27.0 g of an unknown compound reveals that it contains 7.0 g of nitrogen and 20.0 g of oxygen. (At. Wts: O = 16, N = 14)

a) What is its empirical formula?


b) If the molar mass of the molecule above is 108 g, what is its molecular formula?

 

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