BY CHECKING THE REACTIVITY OF AN ELEMENT WHICH IS MOST REACTIVE OR NOT AND YOU STUDY TYPE OF CHEMICAL REACTION IN 1 CH AND YOU CHECK THE REACTIVITY OF ELEMENTS IN 3 CH METALS AND NON METALS PAGE NO 45 IN NCERT BOOK
Ice melts when heat energy causes the molecules to move faster, breaking the hydrogen bonds between molecules to form liquid water.
Answer: 4m/s2 (B)
Explanation:
Force = mass × acceleration
Force given is 8N
Mass=2kg
Acceleration =?
Substitute into the formula
F=ma
8=2a
A=8/2
A=4m/s2
Acceleration used is 4m/s2 (B)
Answer:
3.00 mol
Explanation:
Given data:
Mass of P₄ = 211 g
Mass of oxygen = 240 g
Moles of P₂O₅ = ?
Solution:
Chemical equation:
P₄ + 5O₂ → 2P₂O₅
Number of moles of P₄:
Number of moles = mass/ molar mass
Number of moles = 211 g / 123.88 g/mol
Number of moles = 1.7 mol
Number of moles of O₂ :
Number of moles = mass/ molar mass
Number of moles = 240 g / 32g/mol
Number of moles = 7.5 mol
Now we will compare the moles of product with reactant.
O₂ : P₂O₅
5 : 2
7.5 : 2/5×7.5 = 3.00
P₄ : P₂O₅
1 : 2
1.7 : 2×1.7 = 3.4 mol
Oxygen is limiting reactant so the number of moles of P₂O₅ are 3.00 mol.
Mass of P₂O₅:
Mass = number of moles × molar mass
Mass = 3 mol ×283.9 g/mol
Mass = 852 g
The mass of sodium sulphate, Na₂SO₄, required to prepare the solution is 10.65 g
<h3>How to determine the mole of sodium sulphate Na₂SO₄</h3>
- Volume = 250 mL = 250 / 1000 = 0.25 L
- Molarity = 0.3 M
Mole = Molarity x Volume
Mole of Na₂SO₄ = 0.3 × 0.25
Mole of Na₂SO₄ = 0.075 mole
<h3>How to determine the mass of sodium sulphate Na₂SO₄</h3>
- Molar mass of Na₂SO₄ = 142.05 g/mol
- Mole of Na₂SO₄ = 0.075 mole
Mass = mole × molar mass
Mass of Na₂SO₄ = 0.075 × 142.05
Mass of Na₂SO₄ = 10.65 g
Thus, 10.65 g of Na₂SO₄ is needed to prepare the solution.
Learn more about molarity:
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