KBr (potassium bromide) contains 32.9% by weight of potassium. If 6.40 g of bromine react with 3.60 g of potassium, calculate the number of moles of potassium which combine with bromine to form KBr.

Explanation

To solve the problem, we need to determine how many moles of potassium (K) react with a given mass of bromine (Br) to form potassium bromide (KBr). We will follow these steps:

### Step 1: Determine the mass of potassium that reacts with bromine
Given that KBr contains 32.9% by weight of potassium, we can find the ratio of potassium to bromine in KBr.

- The percentage of bromine in KBr = 100% - 32.9% = 67.1%
- This means that for every 32.9 g of potassium, there are 67.1 g of bromine.

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