Question

1- Write postulates of Dalton's atomic theory.

2-Write law of conservation of mass.

    Give three examples.

3-Write law of constant proportion.

     Give three examples.

4- What is formula mass?

5- Write formula and mass of Calcium Sulphite,

Calcium carbonate, Sodium Carbonate

6- Calculate mass of oxygen atom in 

  a) 20g of Calcium carbonate

  b) 71 gm of Sodium Sulphate

PLS ANSWER IT IN SHORT PLSSS​

Answer 1

Explanation:

1- All matter consists of indivisible particles called atoms. Atoms of the same element are similar in shape and mass, but differ from the atoms of other elements. Atoms cannot be created or destroyed. Atoms of different elements may combine with each other in a fixed, simple, whole number ratios to form compound atoms

2-The law of conservation of mass states that matter cannot be created or destroyed in a chemical reaction. For example, when wood burns, the mass of the soot, ashes, and gases, equals the original mass of the charcoal and the oxygen when it first reacted.

3- The law of constant composition says that, in any particular chemical compound, all samples of that compound will be made up of the same elements in the same proportion or ratio. For example, any water molecule is always made up of two hydrogen atoms and one oxygen atom in a 2:1 ratio

4-This quantity is called the formula massThe sum of the masses of the elements in the formula of an ionic compound.. The formula mass is obtained by adding the masses of each individual atom in the formula of the compound.

5-Calcium sulfite: CaSO3

Calcium carbonate: CaCO3

Sodium carbonate: : Na₂CO

6: Sodium carbonate + Ethanoic acid → Sodium ethanoate + Carbon dioxide + Water

5.3 g + 6 g → 8.2 g + 2.2 g + 0.9 g

LHS RHS

11.3 g = 11.3 g

(Mass of reactant) (Mass of product)

This shows, that during a chemical reaction mass of reactact = mass of product.

hope it helps

Answer 2

1] All matter consists of indivisible particles called atoms. Atoms of the same element are similar in shape and mass, but differ from the atoms of other elements. Atoms cannot be created or destroyed. Atoms of different elements may combine with each other in a fixed, simple, whole number ratios to form compound atoms.

2]The law of conservation of mass states that matter cannot be created or destroyed in a chemical reaction. For example, when wood burns, the mass of the soot, ashes, and gases, equals the original mass of the charcoal and the oxygen when it first reacted. So the mass of the product equals the mass of the reactant.

3]The law of constant proportions states that chemical compounds are made up of elements that are present in a fixed ratio by mass. ... For example, in a nitrogen dioxide (NO2) molecule, the ratio of the number of nitrogen and oxygen atoms is 1:2 but the mass ratio is 14:32 (or 7:16).

4]The formula mass of a substance is the sum of the average atomic masses of each atom represented in the chemical formula and is expressed in atomic mass units.

5]

CaSO3

Calcium sulfite/Formula

mass = 120.17g/mol

CaCO3

calcium carbonate \ formula

mass= 100.0869 g/mol

Na₂CO₃

sodium carbonate\formula

mass= 105.9888 g/mol

6]

a]The number of O2 oxygen atoms in 20g of CaCO3 would be 1.8069*10 ²³ atoms

b] the number of O2 oxygen atoms in 71g of Na2SO4 weeks be 96.352*10²³ atoms.

I'm not so good in chem.

I have tried my best .

hope it may help you.