Question 1:

The balanced chemical equation is:

From the equation, 1 mole of Pb(NO₃)₂ reacts with 2 moles of KI to produce 1 mole of PbI₂.

To produce 0.30 moles of PbI₂:

• Moles of Pb(NO₃)₂ needed = 0.30×1=0.30 mol

• Moles of KI needed = 0.30×2=0.60 mol

That matches option C.

*These A.I. responses have been individually checked to ensure they match the accepted answer, but explanations may still be incorrect. Responses may give guidance but the A.I. might not be able to answer the question! This is particularly the case for questions based on diagrams, which the A.I. typically cannot interpret.
Grade Gorilla uses Gemini, Deepseek and a range of other A.I. chatbots to generate the saved responses. Some answers have had human intervention for clarity or where the A.I. has not been able to answer the question.

Question 2:

The balanced equation is:

From the equation, 1 mole of CaCO₃ produces 1 mole of CO₂.

So, 0.2 moles of CaCO₃ will produce 0.2 moles of CO₂.

Now, calculate the molar mass of CO₂:

• C = 12

• O = 16 (and there are 2 oxygen atoms)

Mass of CO₂ produced:

So, the correct answer is D. 8.8g.

*These A.I. responses have been individually checked to ensure they match the accepted answer, but explanations may still be incorrect. Responses may give guidance but the A.I. might not be able to answer the question! This is particularly the case for questions based on diagrams, which the A.I. typically cannot interpret.
Grade Gorilla uses Gemini, Deepseek and a range of other A.I. chatbots to generate the saved responses. Some answers have had human intervention for clarity or where the A.I. has not been able to answer the question.

Question 3:

The balanced equation is:

From the equation, 1 mole of Fe produces 1 mole of FeSO₄.

Step 1: Calculate moles of FeSO₄ produced.

Given: mass of FeSO₄ = 7.6 g, and Mr of FeSO₄ = 152 g/mol.

Step 2: Find moles of Fe needed.

Since the mole ratio is 1:1, moles of Fe needed = 0.05 moles.

Step 3: Calculate mass of Fe.

So, the correct answer is A. 2.8g.

*These A.I. responses have been individually checked to ensure they match the accepted answer, but explanations may still be incorrect. Responses may give guidance but the A.I. might not be able to answer the question! This is particularly the case for questions based on diagrams, which the A.I. typically cannot interpret.
Grade Gorilla uses Gemini, Deepseek and a range of other A.I. chatbots to generate the saved responses. Some answers have had human intervention for clarity or where the A.I. has not been able to answer the question.

Question 4:

The balanced equation is:

From the equation, 2 moles of Mg produce 2 moles of MgO, so the mole ratio is 1:1.

Step 1: Calculate moles of Mg.

Given: mass of Mg = 2.4 g, and Ar of Mg = 24.

Step 2: Find moles of MgO produced.

Since the ratio is 1:1, moles of MgO = 0.1 moles.

Step 3: Calculate mass of MgO.

Molar mass of MgO = 24 + 16 = 40 g/mol.

So, the correct answer is B. 4.0g.

*These A.I. responses have been individually checked to ensure they match the accepted answer, but explanations may still be incorrect. Responses may give guidance but the A.I. might not be able to answer the question! This is particularly the case for questions based on diagrams, which the A.I. typically cannot interpret.
Grade Gorilla uses Gemini, Deepseek and a range of other A.I. chatbots to generate the saved responses. Some answers have had human intervention for clarity or where the A.I. has not been able to answer the question.

Question 5:

To solve this, we need to calculate both the formula mass (relative formula mass) of Fe₂O₃ and the number of moles in 320 kg.

Step 1: Calculate the formula mass of Fe₂O₃.

• Atomic mass of Fe = 56

• Atomic mass of O = 16

So, the formula mass is 160.

Step 2: Calculate the number of moles in 320 kg.

First, convert 320 kg to grams:

Now, use the formula:

So, the number of moles is 2000.

Step 3: Match with the options.

• Formula mass = 160

• Moles = 2000

This matches option C.

*These A.I. responses have been individually checked to ensure they match the accepted answer, but explanations may still be incorrect. Responses may give guidance but the A.I. might not be able to answer the question! This is particularly the case for questions based on diagrams, which the A.I. typically cannot interpret.
Grade Gorilla uses Gemini, Deepseek and a range of other A.I. chatbots to generate the saved responses. Some answers have had human intervention for clarity or where the A.I. has not been able to answer the question.

Question 6:

To find the mass of iron obtained, we use the balanced equation:

From the equation, 1 mole of Fe₂O₃ produces 2 moles of Fe.

Step 1: Moles of Fe₂O₃ in 320 kg.

From the previous question, we already calculated:

• Molar mass of Fe₂O₃ = 160 g/mol

• Mass = 320 kg = 320,000 g

Step 2: Moles of Fe produced.

Using the 1:2 ratio:

Step 3: Mass of Fe produced.

Atomic mass of Fe = 56 g/mol.

Convert to kg:

So, the correct answer is B. 224 kg.

*These A.I. responses have been individually checked to ensure they match the accepted answer, but explanations may still be incorrect. Responses may give guidance but the A.I. might not be able to answer the question! This is particularly the case for questions based on diagrams, which the A.I. typically cannot interpret.
Grade Gorilla uses Gemini, Deepseek and a range of other A.I. chatbots to generate the saved responses. Some answers have had human intervention for clarity or where the A.I. has not been able to answer the question.

Question 7:

To solve this, we need to calculate the moles of magnesium and then determine which reagent is in excess.

Step 1: Calculate moles of magnesium.

• Mass of Mg = 0.096 g

• Atomic mass of Mg = 24 g/mol

Step 2: Determine the required moles of HCl for complete reaction.

From the balanced equation:

1 mole of Mg reacts with 2 moles of HCl.

So, for 0.004 moles of Mg:

Step 3: Compare with available HCl.

Available HCl = 0.006 moles.

Since 0.006 < 0.008, HCl is the limiting reagent, and Mg is in excess.

Step 4: Match with the options.

• Moles of Mg = 0.004

• Reagent in excess = magnesium

This matches option A.

*These A.I. responses have been individually checked to ensure they match the accepted answer, but explanations may still be incorrect. Responses may give guidance but the A.I. might not be able to answer the question! This is particularly the case for questions based on diagrams, which the A.I. typically cannot interpret.
Grade Gorilla uses Gemini, Deepseek and a range of other A.I. chatbots to generate the saved responses. Some answers have had human intervention for clarity or where the A.I. has not been able to answer the question.

Question 8:

To determine the correct answer, follow these steps:

Step 1: Find the moles of metal X that reacted.

From the balanced equation:

The mole ratio of X to O₂ is 4:1.

Given: moles of O₂ = 0.05 mol

Step 2: Calculate the relative atomic mass (Ar) of X.

Given: mass of X = 7.8 g, and moles of X = 0.20 mol.

Step 3: Match with the options.

• Moles of X = 0.2

• Relative atomic mass = 39

This matches option C.

*These A.I. responses have been individually checked to ensure they match the accepted answer, but explanations may still be incorrect. Responses may give guidance but the A.I. might not be able to answer the question! This is particularly the case for questions based on diagrams, which the A.I. typically cannot interpret.
Grade Gorilla uses Gemini, Deepseek and a range of other A.I. chatbots to generate the saved responses. Some answers have had human intervention for clarity or where the A.I. has not been able to answer the question.

Question 9:

To solve this, follow these steps:

Step 1: Calculate the moles of glucose fermented.

Given:

• Mass of glucose = 90 g

• Mr of glucose = 180 g/mol

Step 2: Find the moles of ethanol produced.

From the balanced equation:

The mole ratio of glucose to ethanol is 1:2.

So:

Step 3: Match with the options.

• Moles of glucose = 0.5

• Moles of ethanol = 1

This matches option D.

*These A.I. responses have been individually checked to ensure they match the accepted answer, but explanations may still be incorrect. Responses may give guidance but the A.I. might not be able to answer the question! This is particularly the case for questions based on diagrams, which the A.I. typically cannot interpret.
Grade Gorilla uses Gemini, Deepseek and a range of other A.I. chatbots to generate the saved responses. Some answers have had human intervention for clarity or where the A.I. has not been able to answer the question.

Question 10:

To find the simplest whole number ratio of moles of NaHCO₃ decomposed to Na₂CO₃ formed, follow these steps:

Step 1: Calculate moles of NaHCO₃ decomposed.

Given:

• Mass of NaHCO₃ = 3.36 g

• Mr of NaHCO₃ = 84 g/mol

Step 2: Calculate moles of Na₂CO₃ formed.

Given:

• Mass of Na₂CO₃ = 2.12 g

• Mr of Na₂CO₃ = 106 g/mol

Step 3: Find the mole ratio.

=2:1 ratio.

Step 4: Match with the options.

The ratio is 2:1, which corresponds to option B.

*These A.I. responses have been individually checked to ensure they match the accepted answer, but explanations may still be incorrect. Responses may give guidance but the A.I. might not be able to answer the question! This is particularly the case for questions based on diagrams, which the A.I. typically cannot interpret.
Grade Gorilla uses Gemini, Deepseek and a range of other A.I. chatbots to generate the saved responses. Some answers have had human intervention for clarity or where the A.I. has not been able to answer the question.