Answer:- The volume of copper is 280 mL.
Solution:- Density and mass of copper metal are given and it asks to calculate the volume of it.
Density is directly proportional to mass and inversely proportional to the volume. The density formula is:

where D stands for density, M stands for mass and V stands for volume.
Since, the problem asks to calculate the volume, let's rearrange the formula for volume.

The given density is 8.9 grams per mL and the mass is 2.5 kg. We need to convert the mass unit from kg to g so that the g unit could be canceled while calculating volume.
The conversion factor is, 1kg = 1000g

= 2500g
Let's plug in the values in the density formula to calculate the volume.

= 280.89 mL
If the sig figs are considered then the answer needs to be round to two sig figs and hence the volume becomes 280 mL.
Carbon and hydrogen and the number next to is the number of moles
Answer:Barometer :
Barometer is a scientific device. It is used to measure air pressure in environment. Air pressure changes with distance upper and bottom sea level.
Barometer is also used for measure altitude.
Barometric pressure has main effects on water and atmosphere conditions.
Hence, Barometer is used to measure air pressure.
Explanation:
t can be transferred from one region to the other. In solids heat is transferred by a process called conduction. In vacuum heat transfer is by a process called radiation. In fluids (gases and liquids) heat is transferred by a process known as convection.
nebula is an interstellar cloud of dust, hydrogen, helium and other ionized gases. although denser than the space surrounding them, most nebulae are far less dense than any vacuum created on earth – a nebular cloud the size of the earth would have a total mass of only a few kilograms. (wikipedia)
hope this helps! ❤ from peachimin