化學式、方程式與物質的量：练习题

What is the concentration of a solution containing \(0.200\text{ moles}\) of sodium chloride dissolved in \(250\text{ cm}^3\) of solution?

What is the atom economy by mass for the production of iron from iron(III) oxide in the blast furnace according to the equation:
\( Fe_2O_3 + 3CO \rightarrow 2Fe + 3CO_2 \)?
(Relative atomic masses: \( Fe = 55.8, O = 16.0, C = 12.0 \))

A reaction is performed to produce titanium from titanium(IV) chloride using magnesium as shown in the equation below:

\(\text{TiCl}_4 + 2\text{Mg} \rightarrow \text{Ti} + 2\text{MgCl}_2\)

In an industrial process, \(1.90\text{ tonnes}\) of \(\text{TiCl}_4\) reacts with an excess of magnesium to produce \(0.432\text{ tonnes}\) of titanium. What is the percentage yield of titanium in this process?
(Relative atomic masses: \(\text{Cl} = 35.5, \text{Ti} = 47.9\))

Which of the following is the correct definition for the term empirical formula?

A gas occupies \( 1.20\text{ dm}^3 \) at a pressure of \( 100\text{ kPa} \) and a temperature of \( 300\text{ K} \). Using the ideal gas equation \( pV = nRT \), calculate the amount of gas in moles.
(Gas constant \( R = 8.31\text{ J mol}^{-1}\text{ K}^{-1} \))

Calculate the relative formula mass of hydrated copper(II) sulfate, \( \text{CuSO}_4 \cdot 5\text{H}_2\text{O} \).
(Relative atomic masses: \( \text{Cu} = 63.5, \text{S} = 32.1, \text{O} = 16.0, \text{H} = 1.0 \))

Determine the volume, in \( \text{cm}^3 \), occupied by \( 0.250\text{ mol} \) of an ideal gas at a pressure of \( 150\text{ kPa} \) and a temperature of \( 323\text{ K} \).
(Gas constant \( R = 8.31\text{ J mol}^{-1}\text{ K}^{-1} \))

A solution of sodium hydroxide contains \( 2.00\text{ g} \) of \( NaOH \) dissolved in \( 500\text{ cm}^3 \) of deionised water. Calculate the concentration of the solution in \( \text{mol dm}^{-3} \).
(Relative atomic masses: \( Na = 23.0, O = 16.0, H = 1.0 \))

The reaction between calcium carbonate and hydrochloric acid is shown by the following equation:
\( CaCO_{3}(s) + 2HCl(aq) \rightarrow CaCl_{2}(aq) + H_{2}O(l) + CO_{2}(g) \)

(a) Calculate the mass of calcium carbonate required to produce \( 240 \text{ cm}^{3} \) of carbon dioxide gas at room temperature and pressure. (Molar volume of gas at RTP = \( 24.0 \text{ dm}^{3} \text{ mol}^{-1} \); \( M_{r} \) of \( CaCO_{3} = 100.1 \))
(b) Write the ionic equation, including state symbols, for this reaction.