8) Pumice and obsidian are both forms of volcanic glass. What are one similarity and one difference in the
composition of these two rocks? (p.150)
pumice
• igneous extrusive rock
composed largely of silica;
light in color, light enough to
float on water
• commonly used in soaps
and cleansers, concrete and
plaster
obsidian
igneous extrusive rock
composed largely of silica:
dark due todark-colored
minerals distributed within
• commonly used to make
jewelry and surgical
instruments

NEED ANSWER RIGHT NOW

a patient chooses to not take a beneficial medical treatment.

explanation:

1. a)c-14 has two more protons

2. d)they have different numbers of protons, neutrons, and valence electrons; they are all gases at room temperature.

3. c) iron and nickel.

substituting a hydrogen atom with a halogen in a hydrocarbon:

- the single bond remains single. a is wrong.

- the bond with hydrogen is as strong as with a halogen. c is wrong

- a hydrocarbon is saturated if there is no double bond. we do not know that so d is wrong.

- carbon will always have four valence electrons. e is wrong.

by elimination, the correct answer is b. the boiling point of the new compound increases.