Question

which of the following is the si base unit for mass?
l
g
kg
s
question 9 (0.5 points)
which of the following represents the smallest mass?
4.0×10^0 mg
4.0×10^2 ng
4.0×10^(-4) g
4.0×10^2 μg

Explanation:

Step1: Recall SI base - unit for mass

The SI base - unit for mass is the kilogram (kg). The symbol 'L' is for liter (volume), 'g' is gram (a derived unit of mass), and 's' is for second (time).

Step2: Convert all mass values in question 9 to grams

1. For $4.0\times10^{0}\text{ mg}$:

• Since $1\text{ mg}=10^{- 3}\text{ g}$, then $4.0\times10^{0}\text{ mg}=4.0\times10^{0}\times10^{-3}\text{ g}=4.0\times10^{-3}\text{ g}$.

1. For $4.0\times10^{2}\text{ ng}$:

• Since $1\text{ ng}=10^{-9}\text{ g}$, then $4.0\times10^{2}\text{ ng}=4.0\times10^{2}\times10^{-9}\text{ g}=4.0\times10^{-7}\text{ g}$.

1. For $4.0\times10^{-4}\text{ g}$, it is already in grams.
2. For $4.0\times10^{2}\text{ }\mu\text{g}$:

• Since $1\text{ }\mu\text{g}=10^{-6}\text{ g}$, then $4.0\times10^{2}\text{ }\mu\text{g}=4.0\times10^{2}\times10^{-6}\text{ g}=4.0\times10^{-4}\text{ g}$.

Step3: Compare the values

Comparing $4.0\times10^{-3}\text{ g}$, $4.0\times10^{-7}\text{ g}$, $4.0\times10^{-4}\text{ g}$, and $4.0\times10^{-4}\text{ g}$, we can see that $4.0\times10^{-7}\text{ g}$ (which is $4.0\times10^{2}\text{ ng}$) is the smallest.

Answer:

First question: C. kg
Second question: B. $4.0\times10^{2}\text{ ng}$