Answer: 
Explanation: 1 gram is equal to 1000 Milligrams so

Since you go straight across its just multiplication so 0.00200x1000=200mg
To answer it in scientific notation it should just be
mg
Answer:
8.9 g / cm^3
Explanation:
Density = mass / volume
We are given volume which is 10.0cm^3 (cm^3 is just fancy way of saying ml), and mass of 89 gram. Just plug them in respective spots.
Density = 89 / 10.0 = 8.9 g / cm^3
Answer:
773.43 torr
Explanation:
From the question given above, the following data were obtained:
Pressure (in inHg) = 30.45 inHg
Pressure (in torr) =?
We can convert 30.45 inHg to torr by doing the following:
1 inHg = 25.4 torr
Therefore,
30.45 inHg = 30.45 inHg × 25.4 torr / 1 inHg
30.45 inhg = 773.43 torr
Thus, 30.45 inhg is equivalent to 773.43 torr