Generate for me chemistry questions and answers on kcse prediction 2026 paper one

Here are some potential chemistry questions and their answers for the KCSE Paper One prediction for 2026:

1. Question: Balance the following chemical equation:

   $\text{C}_3\text{H}_8 + \text{O}_2 \rightarrow \text{CO}_2 + \text{H}_2\text{O}$

   Answer:

   Step 1: Write the unbalanced equation:

   $\text{C}_3\text{H}_8 + \text{O}_2 \rightarrow \text{CO}_2 + \text{H}_2\text{O}$

   Step 2: Balance carbon (C):

   3 C on the left, so put 3 in front of $\text{CO}_2$:

   $\text{C}_3\text{H}_8 + \text{O}_2 \rightarrow 3\text{CO}_2 + \text{H}_2\text{O}$

   Step 3: Balance hydrogen (H):

   8 H on the left, so put 4 in front of $\text{H}_2\text{O}$:

   $\text{C}_3\text{H}_8 + \text{O}_2 \rightarrow 3\text{CO}_2 + 4\text{H}_2\text{O}$

   Step 4: Balance oxygen (O):

   Total O on the right = $3 \times 2 + 4 \times 1 = 10$.

   On the left, we need 10 O, so put 5 in front of $\text{O}_2$:

   $\text{C}_3\text{H}_8 + 5\text{O}_2 \rightarrow 3\text{CO}_2 + 4\text{H}_2\text{O}$

   Final Answer: $\boxed{\text{C}_3\text{H}_8 + 5\text{O}_2 \rightarrow 3\text{CO}_2 + 4\text{H}_2\text{O}}$

2. Question: Calculate the number of moles in 50 grams of sodium chloride (NaCl). (Molar mass of NaCl = 58.5 g/mol)

   Answer:

   Step 1: Use the formula for moles:

   $\text{Moles} = \frac{\text{mass (g)}}{\text{molar mass (g/mol)}}$

   Step 2: Substitute the values:

   $\text{Moles} = \frac{50 \, \text{g}}{58.5 \, \text{g/mol}} \approx 0.8547 \, \text{mol}$

   Final Answer: $\boxed{0.85 \, \text{mol}}$

3. Question: What is the pH of a solution with a hydrogen ion concentration of $1 \times 10^{-4} \, \text{mol/L}$?

   Answer:

   Step 1: Use the formula for pH:

   $\text{pH} = -\log[\text{H}^+]$

   Step 2: Substitute the values:

   $\text{pH} = -\log(1 \times 10^{-4}) = 4$

   Final Answer: $\boxed{4}$

Let me know if you need more questions or details! 📚