Chem exam 2

Which pair exhibits predominantly ionic bonding?

RbCl and CaO

PCl5 and HF

Kl and O3

Na2SO3 and BH3

Hydrogen gas (H2) is a promising alternative to fossil fuels. How many grams of molecules are present in 1.0 g of hydrogen gas?

6.0 x 10^26

3.0 x 10^23

6.0 x 10^23

3.0 x 10^26

Single bonds, double bonds and triple bonds

Have 1, 2, and 3 shared electrons, respectively

Have 3, 6, and 9 shared electrons, respectively

Have 2, 4, and 6 shared electrons respectively

Are only possible between carbon atoms

Which of the following is not true? 1)a bond in which an electron pair shared by two atoms is non-polar covalent. 2)boron (B) would have a larger electronegativity than carbon (C). 3)SF4 represents a species in which all atoms follow the octet rule.

1 and 2

2 and 3

1 and 3

Increasing wavelength goes in this order

Uv>visible>infrared

Uv>infrared>visible

Visible>infrared>uv

Infrared>visible>uv

Wavelength is the

Number of waves passing a fixed point in one second

Distance between successive peaks in a wave

Height of the wave

Distance between a peak of one wave and the next trough

The speed of light in air

Is independent of the wavelength and frequency of light

Changes when the energy of the light changes

Changes when the frequency of the light changes

Changes when the wavelength of the light changes

Which statement is not true?

Solid water is less dense than liquid water

In a solution the solvent is found in greater amounts than the solute

When water is the solvent a solution is said to be aqeous

An unsaturated solution cannot dissolve any more solute

How many moles of sodium chloride are there in 250 mL of a 1.20 M sodium chloride solution?

1.2

.30

.60

2.4

"hard" water may have a calcium ion concentration as high as 400 ppm. What is this calcium ion concentration when expressed as a percentage?

0.4%

400%

0.04%

Bases are substances that increase the hydroxide ion concentration in aqueous solution. Why does ammonia (NH3), which doesn't contain a hydroxide group, act as a base?

Ammonia molecules remove protons from water molecules, forming hydroxide ions

Ammonia molecules donate protons to water molecules, forming hydroxide ions

Ammonia acts as a base only in the presence of hydroxide ion-containing compounds

Ammonia acts as a base only in the presence of very strong acids

What is an aquifer?

A solution in which the solvent is water

A holding tank for disinfected water the municipal water works

A water purification system developed by the romans

A large pool of water trapped in sand and gravel below the surface of the earth

Chem exam 2

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