Question

200 грамм смеси карбоната и гидрокарбоната натрия нагревали до постоянной массы . Масса твердого остатка составила 138грам . Определите состав исходной смеси в массовых процентов

Answer 1

х-масса Na2CO3, 200-x- масса NaHCO3 2NaHCO3=Na2CO3 +CO2+H2O Мr(NaHCO3)=84 Mr(Na2CO3)=106 Получаем пропорцию 200-х/168=138-x/106 x=32 16% NaHCO3 и 84%Na2CO3.  

Answer 2

Calculating the Composition of the Initial Mixture

To determine the composition of the initial mixture of sodium carbonate and sodium hydrogencarbonate in mass percentages, we can use the information about the mass of the solid residue after heating the mixture.

Given: - Mass of the mixture before heating (initial mass) = 200 grams - Mass of the solid residue after heating = 138 grams

We can calculate the composition of the initial mixture using the following steps:

1. Calculate the mass of the substances that were lost during heating. 2. Determine the mass of each substance in the initial mixture. 3. Calculate the mass percentage of each substance in the initial mixture.

Step 1: Calculate the Mass of the Substances Lost During Heating

The mass of the substances lost during heating can be calculated by subtracting the mass of the solid residue from the initial mass of the mixture.

Mass of substances lost = Initial mass - Mass of solid residue Mass of substances lost = 200g - 138g Mass of substances lost = 62g

Step 2: Determine the Mass of Each Substance in the Initial Mixture

Let's assume: - Mass of sodium carbonate in the initial mixture = x grams - Mass of sodium hydrogencarbonate in the initial mixture = y grams

We know that the sum of the masses of the two substances equals the initial mass of the mixture: x + y = 200g

Step 3: Calculate the Mass Percentage of Each Substance in the Initial Mixture

The mass percentage of each substance in the initial mixture can be calculated using the following formulas:

Mass percentage of sodium carbonate = (mass of sodium carbonate / initial mass) * 100 Mass percentage of sodium hydrogencarbonate = (mass of sodium hydrogencarbonate / initial mass) * 100

We can solve for the mass percentages using the values obtained in the previous steps.

Let's proceed with the calculations.