Matter and Change-Unit 1-Chemistry

Which statement describes the composition of potassium chlorate, KClO3

• The proportion by mass of elements combined in potassium chlorate is fixed

• The proportion by mass of elements combined in potassium chlorate is varies

• Potassium chlorate is composed of four elements

• Potassium chlorate is composed of five elements

Two solid samples each contain sulfur, oxygen, and sodium, only. These samples have the same color, melting point, density, and reaction with an aqueous barium chloride solution. It can be concluded that the two samples are the same

• Compound

• Mixture

• Element

• Solution

Which substance can be decomposed by chemical means?

• ammonia

• phosphorus

• oxygen

• silicon

Two substances, A and Z, are to be identified. Substance A can not be broken down by a chemical change. Substance substance Z can be broken down by a chemical change. What can be concluded about these substances?

• both substances are elements

• both substances are compounds

• substance A is an element and substance Z is a compound

• substance A is a compound and substance Z is a element

Which statement correctly describes two forms of oxygen, O2 and O3?

• They have identical molecular structures and identical properties.

• They have identical molecular structures and different properties.

• They have different molecular structures and identical properties.

• They have different molecular structures and different properties.

An iron bar at 325 Kelvin is placed in a sample of water. The iron bar gains energy from the water the temperature of the water is

• 65 K

• 65*C

• 45 K

• 45*C

Which Kelvin temperature is equivalent to -24*C?

• 226 K

• 273 K

• 249 K

• 297 K

What is the total charge of the nucleus of a carbon atom?

• -6

• +6

• 0

• +12

Which two particles each have a mass approximately equal to one atomic mass unit?

• Electron and Neutron

• Electron and Positron

• Proton and Electron

• Proton and Neutron

Compared to an atom of phosphorus-31, and atom of sulfur-32 contains

• One less neutron

• One more neutron

• One less proton

• One more proton