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- Benzene, ethane, and ethylene are just three of a large num-ber of hydrocarbons—compounds that contain only carbon and hydrogen. Show how the following data are consistent with the law of multiple proportions.
Problem 82
- The atomic weight of carbon (12.011) is approximately 12 times that of hydrogen (1.008). (a) Show how you can use this knowledge to calculate pos-sible formulas for benzene, ethane, and ethylene (Prob-lem 2.82).
Problem 83
- In addition to carbon monoxide (CO) and carbon dioxide (CO2), there is a third compound of carbon and oxygen called carbon suboxide. If a 2.500 g sample of carbon suboxide contains 1.32 g of C and 1.18 g of O, show that the law of multiple proportions is followed. What is a possible formula for carbon suboxide?
Problem 85
Problem 88c
Label the following statements about J. J. Thomson's cathode-ray tube experiments shown in Figure 2.6 as true or false. (c) The cathode ray is deflected away from a positively charged plate.
Problem 88f
Label the following statements about J. J. Thomson's cathode-ray tube experiments shown in Figure 2.6 as true or false. (f) By measuring the deflection of the cathode ray beam caused by electric fields of known strength, the charge-to-mass ratio of the electron was calculated.
- Which of the following charges is not possible for the over-all charge on an oil droplet in Millikan's experiment? For this problem, we'll round the currently accepted charge of an electron to 1.602 * 10-19 C. (a) -1.010 * 10-18 C (b) -8.010 * 10-19 C (c) -2.403 * 10-18 C
Problem 90
- What discovery about atomic structure was made from the results of Rutherford's gold foil experiment?
Problem 91
- Prior to Rutherford's gold foil experi-ment, the 'plum pudding' model of the atom represented atomic structure. In this model, the atom is composed of elec-trons interspersed within a positive cloud of charge. If this were the correct model of the atom, predict how the results of Rutherford's experiment would have been different. (a) The alpha particles would pass right through the gold foil with little to no deflection. (b) Most of the alpha particles would be deflected back toward the source. (c) Most of the alpha particles would be absorbed by the atom and neither pass through nor be deflected from the gold foil.
Problem 92
Problem 93
A period at the end of sentence written with a graphite pencil has a diameter of 1 mm. If the period represented the nucleus, approximately how large is the diameter of the entire atom in units of m?
Problem 95
A period at the end of sentence written with a graphite pen-cil has a diameter of 1 mm. How many carbon atoms would it take to line up across the period if a single carbon atom has a diameter of 150 pm?
- What is the difference between an atom's atomic number and its mass number?
Problem 96
- What is the difference between an element's atomic number and its atomic weight?
Problem 97
- The subscript giving the atomic number of an atom is often left off when writing an isotope symbol. For example, 6 often written simply as 13C. Why is this allowed?
Problem 98
- Write symbols for the following isotopes: (a) Radon-220 (b) Polonium-210 (c) Gold-197
Problem 102
- Write symbols for the following isotopes: (a) Z = 58 and A = 140 (b) Z = 27 and A = 60
Problem 103
Problem 104a
How many protons, neutrons, and electrons are in each of the following atoms? (a)
Problem 104b
How many protons, neutrons, and electrons are in each of the following atoms? (b)
Problem 104c
How many protons, neutrons, and electrons are in each of the following atoms? (c)
Problem 104d
How many protons, neutrons, and electrons are in each of the following atoms? (d)
Problem 105a
How many protons and neutrons are in the nucleus of the following atoms? (a)
Problem 105b
How many protons and neutrons are in the nucleus of the following atoms? (b)
Problem 105c
How many protons and neutrons are in the nucleus of the following atoms? (c)
Problem 105d
How many protons and neutrons are in the nucleus of the following atoms? (d)
- Identify the following elements: (a)
Problem 106
- Which of the following isotope symbols can't be correct? (a) (b) (c) (d)
Problem 108
Problem 109
The molar mass of HCl is 36.5 g/mol, and the average mass per HCl molecule is 36.5 u. Use the fact that 1 u = 1.6605 * 102 24g to calculate Avogadro's number.
- Fluorine occurs naturally as a single isotope. How many protons, neutrons, and electrons are present in deuterium fluoride (2HF)? (Deuterium is 2H.)
Problem 110
- Hydrogen has three isotopes (1H, 2H, and 3H), and chlorine has two isotopes (35Cl and 37Cl). How many isotopic kinds of HCl are there? Write the formula for each, and state how many protons, neutrons, and electrons each contains.
Problem 111
Problem 113a
(a) The unified atomic mass unit (u) is used to represent the extremely small mass of atoms. How many grams are equivalent to 1 u?
Problem 113b
(b) The mole is a unit used to represent a very large number of atoms. How many atoms are equivalent to 1 mol of atoms?