1. Avogadro's hypothesis. Avogadro hypothesized that equal volumes of all gases (at the same pressure) will have the same number of molecules. From PV=nRT, we know that one mole of gas takes up 22.4 L
2. Mass number. The mass number is the sum of the protons and neutrons in the nucleus so Carbon 12 has an atomic number of 6 which indicates 6 protons, and a mass number of 12 so 12-6 = 6 neutrons.
3. Avogadro's number. Avogadro's number is the number of units in one mole of any substance, which has been defined as 6.02 x10^23
4. Isotopes are the different forms of a single element. They differ in neutrons. One example is Hydrogen which has three isotopes Protium, Deuterium, and Tritium.
5. Atomic mass. The mass of the atom is equal to the sum of the protons and the neutrons as electrons are so small their mass is negligible. This is not exactly the same as the mass number because this number takes into account the different isotopes
6. mole A mole has the same number of entities as 12 grams of carbon 12, it is expressed by Avogadro's number so 1 mole = 6.02 x10^23 atoms or molecules, etc
7. molar mass- the amount that one mole of substance weighs. For carbon 12, 12 grams has one mole of atoms by definition. So for carbon 12, the molar mass is 12 g/mol
-- volume = (length)(width)(height)
-- Since the cube is a cube, its three dimensions are all the same number.
Volume = (2.5cm)(2.5cm)(2.5cm)
Volume = 15.625 cubic cm
-- density = (mass) / (volume)
Density = (1129.56g) / (15.625cm^3)
Density = 72.3 g/cm^3
(roughly 3.2 TIMES the density of the most dense naturally occurring substance on Earth)
Answer:

Explanation:
Acceleration is defined as the change in velocity divided by the time it took to produce such change. The formula then reads:

Where Vf is the final velocity of the object, (in our case 80 m/s)
Vi is the initial velocity of the object (in our case 0 m/s because the object was at rest)
and t is the time it took to change from the Vi to the Vf (in our case 0.05 seconds.
Therefore we have:

Notice that the units of acceleration in the SI system are
(meters divided square seconds)
The internal pressure increases as the gas is heated