Question

additional equation that is not on your reference list! pv = nrt question 7 when znso₄ dissolves in water, what ions are produced? a zn3+ and o- b z+ and nso4- c zn2+ and so42- d zn2+, s2-, and o2- question 8 a solution is prepared that contains 6 g of cacl₂ in 3 l of solution. what is the concentration of cacl₂ in this solution? a 0.2 m b 20 m c 2.0 m d 0.02 m question 9 a sealed flask contains 4 mol of he and 1 mol of ar. the total pressure in the flask is 2.5 atm. what is the partial pressure of ar? a 1.0 atm b 2.5 atm c 2.0 atm d 0.5 atm

Explanation:

Question 7

When \(ZnSO_4\) dissolves in water, it dissociates. The formula \(ZnSO_4\) breaks into \(Zn^{2 + }\) (zinc ion) and \(SO_4^{2 - }\) (sulfate ion) as per the rules of ionic compound dissociation in water.

Step1: Calculate the molar mass of \(CaCO_3\)

The molar mass of \(CaCO_3\): \(M=(40 + 12+3\times16)\space g/mol = 100\space g/mol\)

Step2: Calculate the number of moles of \(CaCO_3\)

Using the formula \(n=\frac{m}{M}\), where \(m = 6\space g\) and \(M = 100\space g/mol\). So \(n=\frac{6\space g}{100\space g/mol}=0.06\space mol\)

Step3: Calculate the concentration

Using the formula \(C=\frac{n}{V}\), where \(n = 0.06\space mol\) and \(V = 3\space L\). So \(C=\frac{0.06\space mol}{3\space L}=0.02\space M\)

Step1: Calculate the mole fraction of \(Ar\)

The total number of moles \(n_{total}=n_{He}+n_{Ar}=4 + 1=5\space mol\). The mole fraction of \(Ar\), \(x_{Ar}=\frac{n_{Ar}}{n_{total}}=\frac{1\space mol}{5\space mol}=0.2\)

Step2: Calculate the partial pressure of \(Ar\)

Using Dalton's law \(P_{Ar}=x_{Ar}\times P_{total}\). Given \(P_{total}=2.5\space atm\). So \(P_{Ar}=0.2\times2.5\space atm = 0.5\space atm\)

Answer:

C. \(Zn^{2+}\) and \(SO_4^{2 - }\)

Question 8