What is the name of this alkane? a) 1-methyl,3-ethylnonane b) 1-methyl,5-ethylisohexane c) 1-ethyl,3-methylcyclohexane d) 1-ethyl,5-methylcyclohexane

C.
The compound has a ring, so it has cyclo in the name.
Always use the smallest numbers to get to the "extensions" that is where the 3 comes from because the methyl attachment is off of the third bond in the ring.

C

C. definite shape, definite volume. that is a solid.

Density= mass/volume so 5.1 divided by 4.7 is  5.1 / 4.7 =1.08510638298round to the correct number of sig figs