Klausur 3 April, Fragen PDF

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Dalia Soueid [email protected]

General Chemistry SI Exam 1 Review

Determine if the following changes are chemical or physical: • Sodium hydroxide dissolves in water • Hydrochloric acid reacts with sodium hydroxide to produce a salt and water • A pellet of sodium is sliced in two • Water is heated and changed to steam • Potassium chlorate decomposes • Iron rusts • Ice melts • Acid on limestone produces carbon dioxide gas • Milk sours • Wood rots • Density • Flammability

________________ ________________ ________________ ________________ ________________ ________________ ________________ ________________ ________________ ________________ ________________ ________________

1. A hamster is measured to run 1000 yards on his/her hamster wheel in a day. What is the hamster’s average speed in proper SI unit notation? (1 in = 2.54 cm).

2. The spiral galaxy M-83 is 3.0 x 106 parsecs away from Earth. One parsec (pc), a unit used in astronomy, is equivalent to 206265 AU (astronomical units), where 1 AU is 1.496 x 108 km. What is the distance between Earth and M-83 in meters?

3. How many liters are there in 57863476 µg of a given substance? The density of the substance is 3.21 g/mL.

4. Oceanographers often express the density of sea water in units of kilograms per cubic meter. If the density of sea water is 1.025 g/cm3 at 15 °C, what is its density in kilograms per cubic meter?

Chapter 2

Remember: Percent abundance refers to how prevalent an isotope of a given element is in nature. All the isotopes of a given element each have a percent abundance, and when they are added together, they must equal 100%.

For example:

Argon has 3 naturally occurring isotopes: 0.337% abundance of Ar-36 _____% abundance of Ar-38 99.63% abundance of Ar-40

1. Bromine has two naturally occurring isotopes. One has a mass of 78.918338 amu and an abundance of 50.69%. What is the mass of the second isotope given the atomic weight of bromine is 79.9 amu?

2. Gallium has two naturally occurring isotopes. The mass of gallium- 69 is 68.9256 amu and it is 60.108% abundant. The mass of gallium- 71 is 70.9247 amu and it is 39.892% abundant. Find the atomic weight of gallium.

Name the following ________________ compounds: a. NF3 b. N2O c. N2O4

d. SF6

e. PCl5

f. S2F10

Now _______________ compounds: a. CaCl2

b. Ca3(PO4)2

c. Na2O

d. NaHCO3

e. Al(ClO3)3

f. AuH2PO4

Now write out the formulas for the following named compounds: a. Potassium nitride b. Strontium nitrite

c. Caesium nitrate

d. Barium sulfide

e. Francium sulfite

f. Aluminum sulfate

g. Lead (II) phosphide

h. Silver (I) phosphate

i. Radium cyanide

j. tetranitrogen decoxide

k. Iodine Heptafluoride

Calculate the mass, in grams, of each of the following: a. 1.25 x 10-3 mol of iron

b. 1.25 x 1033 atoms of aluminum

l. Pentaboron Nonahydride

Calculate the amount of moles for each of the following: b. 876 atoms of lithium

d. 0.983 ng of Xe

Empirical Formula CH

Molar Mass (g/mol) of Molecular Formula 26.0

CHO

116.1

Molecular Formula

C10H20 1. 200 grams of an organic compound is known to contain 83.884 g of carbon, 10.486 g of hydrogen, 18.640 g of oxygen and the rest is nitrogen. What is the empirical formula of the compound?

2. Succinic acid occurs in fungi and lichens. Its empirical formula is C2H3O2, and its molar mass is 118.1 g/mol. What is its molecular formula?...