CHM211

The distance between carbon atoms in ethylene is 134 picometers. Which of the following expresses that distance in meters?

1.34 x 10^-10

Select the answer that expresses the result of this calculation with the correct number of significant figures. 13.602 x 1.90 x3.06/4.2 x 1.4097

13

Ammonium sulfate, (NH4)2SO4, is a fertilizer widely used as a source of nitrogen. Calculate its molecular mass.

132.13 amu

Columns in the periodic table

groups

units of molarity

mol/L

What is the name of Na2O

sodium oxide

Silicon, which makes up about 25% of Earth's crust by mass, is used widely in the modern electronics industry. It has 3 naturally occurring isotopes, 28^Si, 29^Si, and 30^Si. Calculate the atomic mass of silicon.

28.0855 amu

Bromine is the only nonmetal that is a liquid at room temp. Consider the isotope bromine-81, 81/35 Br. Select the combination which list the correct atomic number, neutron number, and mass number, respectively.

35, 46, 81

Isopropyl alcohol, commonly known as rubbing alcohol, boils at 82.4 degrees Celsius. What is the boiling point in K?

355.6 K

Calcuate the number of oxygen atoms in 29.34g of sodium sulfate, Na2S04.

4.976 X 10^23 O atoms

Ammonia will react with fluorine to produce dinitrogen tetrafluoride and hydrogen fluoride (used in production of aluminum, in uranium processing, and in frosting of light bulbs). 2NH3(g) + 5F2(g) → N2F4(g) + 6HF(g) How many moles of NH3 are needed to react completely with 13.6 mol of F2?

5.44 mol

Aluminum reacts with oxygen to produce aluminum oxide, which can be used as an absorbent, desiccant or catalyst for organic reactions. 4Al(s) + 3O2(g) ---> 2Al2O3(s) Amixture of 82.49 g of aluminum (M = 26.98g/mol) and 117.65g of oxygen (M = 32.00g/mol) is allowed to react. Identify the limiting reactant and determine the mass of the excess reactant present in the vessel when the reaction is complete.

Aluminum is the limiting reactant (results in 1.5289 mol of Al2O3-with sig. figs.) Excess reactant: 44.27 g O2

A compound of bromine and flourine is used to make UF6, which is an important chemical in processing and reprocessing of nuclear fuel. The compound contains 58.37 mass percent bromine. Determine its empirical formula.

BrF3

Which of the following is the empirical formula for hexane, C6H14?

C3H7

ionic compound

CACO3

Ammonium

NH4+

Which of the following ions occur commonly?

O^2-

Tetratomic in elemental form

P

A metalloid

Sb

e

electron