Select the following statements that are true. select all that apply.
a. hydrocarbons contain only c and h atoms.
b. names of organic compounds consist of a root for the longest chain, a prefix for any attached group, and a suffix for the type of compound.
c. isomers are compounds with the same molecular formula but different properties.
d. alkynes contain single bonds; alkenes triple bonds and alkanes double bonds.
e. the longer the carbon chain the lower the molar mass and the lower the intermolecular contact, the lower the dispersion forces.

Achemical reaction (also known as a chemical change) produces substances that are chemically different from the starting materials. an example of a chemical reaction is the formation of water from hydrogen and oxygen gas.in a physical change, a substance changes its physical appearance but not its chemical identity. an example of physical change is the formation of liquid water from solid water, a familiar process called melting. physically, liquid water looks very different from solid water (ice) but the chemical identity, water, is the same for both. which of following changes that affect the composition of our atmosphere involve physical changes and which involve chemical reactions? oxygen gas changes to ozone during thunderstorms carbon dioxide is produced by the combustion of gasoline in an automobile engine. when coal, oil, and natural gas are decomposed in landsills they produce methane gas. freezing rain develops when a warm air mass overrides a cold air mass. fog forms from water vapor when the temperature drops below the dew point

What is the independent variable in this investigation? mass volume sample number substance density

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