A crystal or crystalline solid is a solid material whose constituents (such as atoms, molecules, or ions) are arranged in a highly ordered microscopic structure, forming a crystal lattice that extends in all directions. ... Examples of large crystals include snowflakes, diamonds, and table salt.
The answer is D: A metal is added to an acid and hydrogen gas is formed, because that's a chemical reaction
You have to use the molar volume of gas which is 22.4L/mol at STP. To find the number of moles of from a given volume of gas at STP, you need to divide the given volume by 22.4L/mol.
44.4L/22.4L/mol=1.98mol of gas
They start to move around really fast