Answer: 1. magnesium hydroxide + sulfuric acid = magnesium sulphate + water
2. calcium hydroxide + hydrochloric acid = calcium chloride + water
3. lead hydroxide + nitric acid = lead nitrate + water
4. sodium hydroxide + sulfuric acid = sodium sulphate + water
5. potassium hydroxide + citric acid = potassium citrate + water
6. silver hydroxide + hydrochloric acid = silver chloride + water
7. aluminium hydroxide + phosphoric acid = aluminium phosphate + water
Explanation:
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.
The balanced chemical equations are :
1. magnesium hydroxide + sulfuric acid = magnesium sulphate + water

2. calcium hydroxide + hydrochloric acid = calcium chloride + water

3. lead hydroxide + nitric acid = lead nitrate + water

4. sodium hydroxide + sulfuric acid = sodium sulphate + water

5. potassium hydroxide + citric acid = potassium citrate + water

6. silver hydroxide + hydrochloric acid = silver chloride + water

7. aluminium hydroxide + phosphoric acid = aluminium phosphate + water

Answer:
first conclusion was that the whole world is made up of only 4 elements but as the time passed more elements were discovered... if the world would not contain more elements... you wouldn't be alive.
Algae is not an abiotic factor.
Answer:
10
Explanation:
Given endpoints:
E (-2,2) and F(4, -6)
To find the distance between two points;
Use the expression below;
D =
x₁ = -2,
x₂ = 4
y₁ = 2
y₂ = -6
Insert the parameters and solve;
D = 
D =
= 10