Answer:
1. a chemical reaction in which one substance breaks up into two or more new substances: decomposition reaction
2. a reaction in which two or more substances combine to form a new substance: synthesis reaction
3. the reaction of an acid with a base to form a salt and water: neutralization reaction.
4. chemical compound formed when the negative ions from an acid combine with the positive ions of a base: salt
5. two ionic compounds reacting in solution to form two new compounds, one of which is insoluble: double displacement reaction.
6. a reaction in which an active metal displaces a less active metal or hydrogen from a compound solution (or a nonmetal replaces a nonmetal from a compound in solution): Single replacement reaction
Explanation:
1. Decomposition is a type of chemical reaction in which one reactant gives two or more than two products.
Example: 
2. Synthesis reaction is a chemical reaction in which two reactants are combining to form one product.
Example:
3 and 4. Neutralization is a chemical reaction in which an acid and a base reacts to form salt and water. Salt is formed when cations or positive ions of base combine with anions or negative ions of acid.
Here
is the salt formed by combination of
from base and
from acid.
Example: 
5. A double displacement reaction is one in which exchange of ions take place. The salts which are soluble in water are designated by symbol (aq) and those which are insoluble in water and remain in solid form are represented by (s) after their chemical formulas.
Example: 
6. Single replacement reaction is a chemical reaction in which more reactive element displaces the less reactive element from its salt solution.
Example: 
The number of moles in a substance indicates the amount of the substance that contains the same number of particles as 12 g of the Carbon-12 isotope [or equivalent to 6.02 × 10²³] (which is used as a standard in the world of moles).
Now,
if 6.02 × 10²³ atoms are found in 1 mole ofsodium
then let 9.76 × 10¹² atoms are found in x
⇒ x = (9.76 × 10¹² ) ÷ (6.02 × 10²³)
= 1.619 × 10⁻¹¹ mol
Now, mass = moles × molar mass
∴ mass of Na = 1.619 × 10⁻¹¹ mol × 23 g/mol
= 3.72 × 10⁻¹⁰ g
6 km/h west would be your answer
Answer:- 448 mL of hydrogen gas are formed.
Solution:- It asks to calculate the volume of hydrogen gas formed in milliliters at STP when 0.020 moles of magnesium reacts with excess HCl acid. The balanced equation is:

There is 1:1 mol ratio between Mg and hydrogen gas. So, the moles of hydrogen gas is also equals to the moles of Mg reacted.
moles of Hydrogen gas formed = 0.020 mol
At STP, volume of 1 mol of the gas is 22.4 L. We need to calculate the volume of 0.02 moles of hydrogen gas.

= 0.448 L
They want answer in mL. So, let's convert L to mL using the conversion formula, 1L = 1000mL

= 448 mL
So, 0.020 moles of magnesium would produce 448 mL of hydrogen gas at STP on reacting with excess of HCl acid.
The 2nd ionization energy is removing a 2nd electron from that resulting cation:
<span>Li+ --> Li2+ + 1e- </span>