a. Smallest basic units of matter
<u>Atom</u>: An atom is the smallest particles of a substance which may or may not exist in free state but takes part in chemical reactions.
<u>Molecule</u>: A molecule is a substance which exists in free state but doesn't take part in chemical reactions.
<u>Laws</u><u> </u><u>of</u><u> </u><u>chemical</u><u> </u><u>combination</u><u>:</u><u>-</u>
- Law of conservation of mass
- Law of constant proportions
- Law of multiple proportions
- Law of reciprocal proportions
The ratio of reactant in grams would be influenced by the reaction equation and the molar mass of the elements. But the ratio of a reactant needed in grams would be same for a reaction.
If 2 grams of element X combine with 4 grams of element Y to form compound XY, it means the ratio of reactant in grams<span> would be 2:4 or 1:2
The number of element X needed for 28grams of element Y would be:
1/2 * 28grams = 14 grams.</span>
Answer:
3.0 x 10²⁴molecules
Explanation:
Given parameters:
Number of moles of compound = 5moles
Unknown:
Number of molecules = ?
Solution:
A mole is substance that contains the Avogadro's number of particles;
1 mole = 6.02 x 10²³ molecules
5 moles of the compound will give 5 x 6.02 x 10²³ molecules
= 3.0 x 10²⁴molecules
Answer:
Solute = 5 mL; solution = 250 mL
Explanation:
The formula for percent by volume is
If you have 250 mL of a solution that is 2 % v/v,
If there is no change of volume on mixing,
Volume of solution = 250 mL
-Volume of solute = <u> </u><u>5</u><u> </u>
Volume of solvent = 245 mL
