Chemistry 130 (Lecture I-III Review)
Useful Constants, Equations, Conversions:
1 ft. = 12 in. 1 in.= 2.54 cm me=9.1093819×10-31kg
5280 ft= 1 mile 1 mL=1 cm3 Avogadro’s number=6.022141×1023mol-1
1609.3 m= 1 mile 1 kg= 2.2046 lb l=hmv
1 lb= 16 oz. 1 gallon= 3.785 L
Answer
1. Add the following four numbers and report your answer using significant figures: 0.005 + 2.5 cm + 0.50 cm + 0.055 cm = ?a. 3.055 cm
b. 3.06 cm
c. 3.1 cm
d. 3 cm
2. Which of the following wavelengths corresponds to red visible light?
a. 600 µm
b. 650 nm
c. 450 nm
d. 700 pm
3. Which of the following situations can be described as highly precise, but not highly accurate?
a. A dozen 20-ounce sodas that contain exactly 18 ounces of soda
b. Tossing three darts at a dart board with each one located directly in the bullseye
c. Measuring the mass of sugar on a balance and observing very different values each time
d. Sinking ten basketball free throws in a row
4. What is the base SI unit of mass?
a. m
b. g
c. kg
d. J
5. Which of the following statements of Dalton’s Atomic Theory eventually proved false?
a. Elements are made up of tiny particles called atoms
b. Atoms combine to form compounds in small, whole-number ratios
c. Elements are characterized by their mass. Atoms of the same element have the same mass while atoms of different elements have different masses
d. Chemical reactions only rearrange the combination of atoms, but do not change the elements (atoms) themselves
6. The distance after which a wave repeats itself is…
a. the period
b. The amplitude
c. the frequency
d. the wavelength
7. Vinegar, C2H4O2, is another common household item. Vinegar is made of 2 atoms of carbon, 4 atoms of hydrogen, and 2 atoms of oxygen. The fact that no other combination of carbon, hydrogen, and oxygen could be combined to create vinegar
a. Law of Conservation of Matter
b. Law of Multiple Proportions
c. Law of Definite Proportions
d. Dalton’s Atomic Theory
8. Which type of electromagnetic radiation has the greatest energy?
a. X-rays
b. UV-rays
c. Visible light
d. Infrared light
9. The mass of a standard is determined using two balances. The average mass determined by balance #1 is 497.8416g while the average mass determined using balance #2 is 499g. The true mass of the standard is 500.0000g. Which balance is more precise? More accurate?
a. Balance #1 is more precise, but balance #2 is more accurate
b. Balance #1 is more accurate, but balance #2 is more precise
c. Balance #1 and Balance #2 are neither precise nor accurate
d. Balance #1 and Balance #2 are both precise and accurate
10. Which list is assorted in increasing energy?
a. X-rays, radio waves, visible light, microwaves
b. Infrared light, microwaves, ultraviolet light, gamma rays
c. Radio waves, microwaves, visible light, gamma rays
d. Infrared light, x-rays, microwaves, ultraviolet light
11. What were the main conclusions from Rutherford’s gold foil experiment, Milikin’s oil drop experiment, and J.J. Thompson’s cathode ray experiment?
12. Convert 0.4 km3 to mL.
13. Glucose has the molecular formula C6H12O6.
a. What is the mass percent of carbon in one molecule of glucose?
b. What is the mass of carbon present in a 5.00g sample of glucose?
c. The natural abundance of 14C is 0.000000000130% (1.30 × 10-10 %). How many atoms of 14C are present in 5.00g sample of glucose?
14. Calculate the energy of an X-ray that has a wavelength of 7.0 nanometers.
15. 10.0 grams of an unknown element contain 2.906×1022 atoms. How many moles of the element are present? What is the molar mass of the unknown element? What is the identity of the element (Note: You do not have to name the element but provide the chemical symbol)?
16. Magnesium has three naturally occurring isotopes: 24Mg (23.985 amu) which has a 78.99% abundance, 25Mg (24.986 amu) which has a 10.00% abundance and a third isotope with 11.01% abundance. If the average atomic mass of magnesium is
24.3050 amu, what is the mass of the third isotope?
17. Cesium metal is frequently used in photoelectric cells because the amount of energy necessary to eject electrons from a cesium surface is relatively small, only 206.5 kJ/mol. What wavelength of light does this correspond to? What type of light does this correspond to (Infrared, Visible, UV, etc.)?
18. Given that the density of iron is 7.87 g/cm3, and the natural abundance of 54Fe is 5.80%, calculate the number of 54Fe atoms in a 1.00 ft3 block of Fe.
19. The average atomic mass for Ne is 20.1797 amu. Use this to complete the table below. Please report the mass of the unknown isotope to three significant figures.
Isotope / Mass (amu) / Natural Abundance20Ne / 19.992440 / 90.48%
21Ne / 20.993847
9.25%
20. Recently, California has been experiencing the worst drought in its history. Let’s say that a typical rain guage is rectangular in shape with the dimensions 1.0 in (width) × 1.0 in (length) × 10.0 in (height). What is the mass (in grams) of rainwater present in the gauge if the height of the water column is 2.5 in? Assume the density of rainwater to be 1.00 g/cm3.
21. The metal tungsten has a threshold energy of 7.29×10-19J. When a particular light source is used, the maximum kinetic energy of an electron ejected from the surface of tungsten is 1.92×10-19J. Given this information, what wavelength of light is emitted by this light source?
22.
a.) A jeweler bought a diamond at wholesale price, paying $8,535 for a 651mg diamond. How much did the jeweler pay per carat? There are exactly 0.2 grams per carat.
b.) Diamond is made entirely of carbon atoms. How many carbon atoms did she purchase?
23. When ultraviolet light of a certain frequency shine son a zinc surface, an electron is ejected with a kinetic energy of 5.55×10-18J. What is the de Broglie wavelength of the ejected electron?
24. Silicon has three naturally occurring isotopes: 28Si (27.976928 amu), 29Si (28.976496 amu), and 30Si. If the relative abundances of 28Si and 29Si are 92.23% and 4.67%, respectively, what is the atomic mass of 30Si? Give your answer to four significant figures.