Which of the units listed below are smaller than a gram? Select all that apply. ug
ng
mg
kg

µg

ng

mg

Explanation:

1 kilogram(kg)=1 000 g

1 gram(g)=1 g

1 milligram(mg)=0.001 g

1 microgram(µg)=0.000 001 g

1 nanogram(ng)=0.000 000 001 g

"standard molar enthalpy:

h2o ( liquid water ) : - 285.8 kj/mole

h2o ( water vapor ) : - 241.8 kj / mole.

δhrxn = - 241. 8 - ( - 285.8 )= -241.8 + 285.8 = 44.0

answer: 44.0 kj"

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.