To calculate the average atomic weight, each exact atomic weight is multiplied by its percent abundance, then, add the results together. If the natural abundance of 63Cu is assigned x, the natural abundance of 65Cu is 1-x (the two abundance always add up to 1). So the solution is: (63)(x)+(65)(1-x) = 63.55, 63x+65-65x=63.55, x=0.725=72.5%. The natural abundance of 63Cu is 72.5%, that of 65Cu is 1-72.5%=27.5%.
Answer:
514.5 g.
Explanation:
- The balanced equation of the reaction is: 2NaOH + H₂SO₄ → Na₂SO₄ + 2H₂O.
- It is clear that every 2.0 moles of NaOH react with 1.0 mole of H₂SO₄ to produce 1.0 mole of Na₂SO₄ and 2.0 moles of 2H₂O.
- Since NaOH is in excess, so H₂SO₄ is the limiting reactant.
- We need to calculate the no. of moles of 355.0 g of H₂SO₄:
n of H₂SO₄ = mass/molar mass = (355.0 g)/(98.0 g/mol) = 3.622 mol.
Using cross multiplication:
∵ 1.0 mol H₂SO₄ produces → 1.0 mol of Na₂SO₄.
∴ 3.622 mol H₂SO₄ produces → 3.662 mol of Na₂SO₄.
- Now, we can get the theoretical mass of Na₂SO₄:
∴ mass of Na₂SO₄ = no. of moles x molar mass = (3.662 mol)(142.04 g/mol) = 514.5 g.
The first word could be: pairs and the second: relax
Answer:
Democritus
Explanation:
He spoke about matter was made of tiny particles which moved in empty space
Explanation:
Sugar - Pure substance
Magnesium Ribbon - Pure Substance
Vegetable soup Heterogeneous mixture
Bath oil - Homogeneous mixture
Tin of assorted biscuits - Heterogeneous mixture
Peanuts and raisins - Heterogeneous mixture
Copper wire - Pure Substance
Bicarbonate of soda (Baking soda) - Pure Substance
