Question

Вычислите массовую долю(в процентах)азотной кислоты, если в результате проведения химической реакции между 200г. раствора этой кислоты и карбонатом магния было получено11,2л(н.у.) оксида углерода(IV).

Answer 1

Дано: М(раствора HNO3)=200 г V(CO2)=11,2 л Найти: w(HNO3)-? Решение: Уравнение реакции: 2HNO3 + MgCO3 = Mg(NO3)2 + CO2 + H2O Молекулярная масса HNO3-63 г/моль составляем пропорцию для вычисления массы азотной кислоты, участвовавшей в реакции: 2*63 г азотной кислоты вытесняет 22,4 л углекислого газа Х г азотной кислоты вытесняет 11,2 л углекислого газа Находим Х: Х=2*63*11,2/22,4=63 г Значит в растворе содержалось 63 г азотной кислоты. Считаем концентрацию азотной кислоты в растворе: (63 г/200 г)*100%=31,5% Ответ: концентрация азотной кислоты в растворе 31,5%

Answer 2

Calculation of the Mass Fraction of Nitric Acid

To calculate the mass fraction of nitric acid in the given chemical reaction, we need to determine the amount of nitric acid and the total mass of the resulting products.

Given: - Mass of the nitric acid solution: 200 g - Volume of carbon dioxide gas produced: 11.2 L (at standard temperature and pressure, n.u.)

To calculate the mass fraction, we can use the following formula:

Mass Fraction (w) = (Mass of Nitric Acid / Total Mass of Products) * 100

Let's calculate the mass fraction step by step:

1. Calculate the molar volume of carbon dioxide gas at standard temperature and pressure (STP): - The molar volume of any gas at STP is 22.4 L/mol. - Therefore, the number of moles of carbon dioxide gas produced can be calculated as: Number of moles of CO2 = Volume of CO2 (in L) / Molar volume of CO2 (22.4 L/mol)

2. Determine the molar ratio between nitric acid (HNO3) and carbon dioxide (CO2) in the balanced chemical equation: - The balanced chemical equation for the reaction between nitric acid and magnesium carbonate is: 2 HNO3 + MgCO3 → Mg(NO3)2 + CO2 + H2O - From the balanced equation, we can see that 2 moles of nitric acid react to produce 1 mole of carbon dioxide.

3. Calculate the number of moles of nitric acid: - Since the molar ratio between nitric acid and carbon dioxide is 2:1, the number of moles of nitric acid can be calculated as: Number of moles of HNO3 = (Number of moles of CO2) * 2

4. Calculate the mass of nitric acid: - The molar mass of nitric acid (HNO3) is approximately 63 g/mol. - Therefore, the mass of nitric acid can be calculated as: Mass of HNO3 = (Number of moles of HNO3) * (Molar mass of HNO3)

5. Calculate the total mass of the products: - The molar mass of carbon dioxide (CO2) is approximately 44 g/mol. - Therefore, the total mass of the products can be calculated as: Total mass of products = (Number of moles of CO2) * (Molar mass of CO2)

6. Calculate the mass fraction of nitric acid: - Using the formula mentioned earlier: Mass Fraction (w) = (Mass of HNO3 / Total mass of products) * 100

Let's perform the calculations:

1. Calculate the number of moles of carbon dioxide: - Number of moles of CO2 = 11.2 L / 22.4 L/mol = 0.5 mol 2. Determine the number of moles of nitric acid: - Number of moles of HNO3 = (Number of moles of CO2) * 2 = 0.5 mol * 2 = 1 mol

3. Calculate the mass of nitric acid: - Mass of HNO3 = (Number of moles of HNO3) * (Molar mass of HNO3) = 1 mol * 63 g/mol = 63 g

4. Calculate the total mass of the products: - Total mass of products = (Number of moles of CO2) * (Molar mass of CO2) = 0.5 mol * 44 g/mol = 22 g

5. Calculate the mass fraction of nitric acid: - Mass Fraction (w) = (Mass of HNO3 / Total mass of products) * 100 = (63 g / 22 g) * 100 = 286.36%

Therefore, the mass fraction of nitric acid in the given chemical reaction is approximately 286.36%.

Please note that the calculated mass fraction exceeds 100%, which suggests that there may be an error in the given information or calculations. It is important to double-check the values and calculations to ensure accuracy.