Читать книгу The Easiest Way to Understand Chemistry. Chemistry Concepts, Problems and Solutions - Sergey D Skudaev - Страница 7

All chemical reactions occur in equivalent proportions.

1. How many grams of Ca Cl2 are spent in the following reaction:

10g?g

Na2CO3 + Ca Cl2 = CaCO3 +2NaCl

All compounds react with each other in certain proportions. In a given reaction one mole of Na2CO3 reacts with one mole of CaCl2

A mole is MW (Molecular mass) in grams.

For Na2CO3 MW is 23 *2 +12 +48 = 106 g. = 1 mole

For CaCl2 MW is 40 +35*2 = 110g. = 1 mole.

106 g Na2CO3 react with 110g CaCl2

10g Na2CO3 react with X g CaCl2

X= 10 * 110 / 106 = 10.38 g CaCl2

2. How many grams of CaCO3 are produced if 100 ml of 0.5 M solution of Na2CO3 reacts with an unlimited volume of solution CaCl2?

0.5 M

2. Na2CO3 + Ca Cl2 = CaCO3 +2 NaCL

100 ml

1 liter of I M solution of Na2CO3 contains 106 g

How many grams of Na2CO3 in 1 liter of 0.5 M solution?

1 M – 106 g

0.5 M – X g

X = 0.5 M * 106 g / 1 M = 53 g

I liter of 0.5 M solution contains 53 grams of Na2CO3

How many grams of Na2CO3 are in 100 ml?

1 liter – 53 g

0.1 liters – X g

X = 0.1 * 53 /1 = 5.3 g

106 g of Na2CO3 produces 100 g of CaCO3

5.3 g of Na2CO3 produces X g of CaCO3

X= 5.3 * 100 / 106 = 5 g