Question

what amount (in mol) of formula units (ionicmolecules) are in 15.8 g of cu(no₃)₂? report you answer in moles and to 3 significant digits (do not include units in answer). question 2 1 pts how many grams are in 0.12 mol of pbso₄? report your answer in grams to 1 decimal place, but do not include units. question 3 1 pts how many molecules of tartrazine, na₃c₁₆h₉n₄o₉s₂, are in 1.84 mol of tartrazine? report your answer in proper scientific notation to the correct number of sig figs by filling in the following blanks, but do not include units in your answer.

Explanation:

Step1: Calculate molar mass of Cu(NO₃)₂

The molar mass of Cu(NO₃)₂: Cu has molar - mass of 63.55 g/mol, N has 14.01 g/mol and O has 16.00 g/mol. So, \(M = 63.55+(2\times14.01)+(6\times16.00)=63.55 + 28.02+96.00 = 187.57\) g/mol.

Step2: Calculate moles of Cu(NO₃)₂

Use the formula \(n=\frac{m}{M}\), where \(m = 15.8\) g and \(M = 187.57\) g/mol. So, \(n=\frac{15.8}{187.57}\approx0.0842\) mol.

Step3: Calculate molar mass of PbSO₄

The molar mass of PbSO₄: Pb has molar - mass of 207.2 g/mol, S has 32.07 g/mol and O has 16.00 g/mol. So, \(M = 207.2+32.07+(4\times16.00)=207.2 + 32.07+64.00 = 303.27\) g/mol.

Step4: Calculate mass of PbSO₄

Use the formula \(m=nM\), where \(n = 0.12\) mol and \(M = 303.27\) g/mol. So, \(m=0.12\times303.27 = 36.4\) g.

Step5: Calculate number of molecules of tartrazine

Use Avogadro's number \(N_A=6.022\times 10^{23}\) molecules/mol. For \(n = 1.84\) mol of tartrazine, the number of molecules \(N=nN_A=1.84\times6.022\times 10^{23}=1.11\times 10^{24}\) molecules.

Answer:

Question 1: 0.0842
Question 2: 36.4
Question 3: 1.11, 24