Conservation of Mass

Q.

Balance the following equation

Al₂(SO₄)₃ +NaOH - Al(OH)₃ +Na₂SO₄

Q.

How would you balance the following equation:
${\mathrm{H}}_2{\mathrm{O}}_2\to {\mathrm{H}}_2\mathrm{O}+{\mathrm{O}}_2$

Q.

Write the word equation for the reaction:

Sodium metal reacts with water to give sodium hydroxide and hydrogen gas.

Q.

Write a balanced chemical equation for barium hydroxide and ammonium chloride. This is exothermic or endothermic?

Q.

How would you balance: $\mathrm{Al}+{\mathrm{Fe}}_2{\mathrm{O}}_3\to {\mathrm{Al}}_2{\mathrm{O}}_3+\mathrm{Fe}$

Q.

Balance the chemical reaction in a single step. $\mathrm{NaOH}\left(\mathrm{aq}\right)+{\mathrm{H}}_2{\mathrm{SO}}_4\left(\mathrm{aq}\right)\to {\mathrm{Na}}_2{\mathrm{SO}}_4\left(\mathrm{aq}\right)+{\mathrm{H}}_2\mathrm{O}\left(\mathrm{l}\right)$

Q.

A chemical equation should be balanced because:

1. mass is conserved in a chemical reaction.

2. number of atoms before and after the reaction is same.

3. the chemical equation should look good.

4. energy is conserved in a chemical reaction.

Q.

What will be the balanced equation of Al +HCl -->AlCl3 + H2 ?

Q.

State laws of chemical combination.

Q.

The law of conservation of mass states ____.

1. that matter can neither be created nor be destroyed in a chemical reaction.

2. that matter can be created as well as destroyed.

3. that matter cannot be created but destroyed in a chemical reaction.

4. that matter can be created but not destroyed.

Q.

How to balance a skeletal equation?

Q.

The chemical equations are balanced to satisfy one of the following laws in chemical reactions. This law known as :

(a) law of conservation of momentum

(b) law of conservation of mass

(c) law of conservation of motion

(d) law of conservation of magnetism

Q.

Balance the following equations:
1. FeCl₃ + NH₄OH → Fe(OH)₃ + NH₄Cl
2. Na₂S₂O₃ + I₂ → Na₂S₄O₆ + NaI

Q.

What are the steps involved in balancing a chemical equation? Explain with examples.

Q.

Write a balanced chemical equation for the given reaction and also classify them: A piece of sodium metal is added to absolute ethanol to form sodium ethoxide and hydrogen gas.

Q.

How does the amount of the reactant change during a chemical reaction?

Q. Give a balanced chemical reaction:
CH₃ CH₂OH to CH₃COOH in presence of Alkaline KMnO₄

Q.

Fill in the following blanks with suitable words :

(a) Chemical equations are balanced to satisfy the law of ..........

(b) A solution made in water in known as an .............. solution and indicated by the symbol .......

Q. Sodium hydrogen carbonate on reaction with hydrochloric acid gives sodium chloride, water and liberates carbon dioxide.

1. $NaHC{O}_3+2HCl\to NaCl+2H_{2}O+C{O}_2$
2. $2NaHC{O}_3+HCl\to 2NaCl+H_{2}O+C{O}_2$
3. $2NaHC{O}_3+HCl\to NaCl+H_{2}O+2C{O}_2$
4. $NaHC{O}_3+HCl\to NaCl+H_{2}O+C{O}_2$

Q.

According to which law, in a physical or chemical change the total mass of the products remain equal to the total mass of the reactants?

1. Law of multiple proportions

2. Gay lussac law

3. Law of conservation of mass

4. Avogadro law

Q.

An unbalanced equation is called _____ equation.

Q. Why is it necessary to balance the number of atoms on both sides of a skeletal chemical equation?

1. Law of conservation of mass
2. The number of atoms are representative of the mass of each element on each side of a chemical reaction
3. The skeletal equation does not show all the elements
4. There has to be a difference between skeletal and balanced equation

Q.

4.5 moles of calcium carbonate are reacted with dilute hydrochloric acid.
(i) Write the equation for the reaction.
(ii) What is the mass of 4.5 moles of calcium carbonate? (Relative molecular mass of calcium carbonate is 100).
(iii) What is the volume of carbon dioxide liberated at stp?
(iv) What mass of calcium chloride is formed? (Relative molecular mass of calcium chloride is 111)
(v) How many moles of HCl are used in this reaction?

Q.

The reaction of potassium permanganate (VII) with acidified iron(II) sulphate is given below:

If 15.8 g of potassium permanganate(VII) was used in the reaction, calculate the mass of iron (II) sulphate used in the above reaction. (K = 39, Mn = 55, Fe = 56, S = 32, O = 16)

1. 46 g

2. 62 g

3. 76 g

4. 54 g

5. 82 g

Q.

CO₂+S₈->CS₂+SO₂

Q.

Shortcut for balancing the equation.

Or

Easiest method for balancing the equation

Q. Balancing the following chemical reaction:
$BaC{l}_2+H_{2}S{O}_4\to BaS{O}_4+HCl$

Q. Potassium metal reacts with water to give potassium hydroxide and hydrogen gas. Write balanced chemical equation for this reaction.

Q. To get a 12% of v/v% of alcohol solution, how much water (in mL) should be mixed with 12 mL of alcohol?

1. 100 mL
2. 12 mL
3. 88 mL
4. 50 mL

Q.

Mass of reactants is equal to mass of products if the reaction has same number of atoms of different elements on either side of the chemical equation respectively.

1. True

2. False