Potassium bromide `KBr` contains `32.9%` potassium by mass. If `6.40 g` of bromine reacts with `3.60 g` of potassium, calculate the number of moles of potassium which combine with bromide to form `KBr`.

Explanation

To solve the problem step by step, we need to determine the number of moles of potassium that react with bromine to form potassium bromide (KBr). Here’s how we can do it:

### Step 1: Determine the mass of bromine that reacts with potassium
The problem states that 6.40 g of bromine reacts with 3.60 g of potassium. We need to find out how much bromine is required for the given amount of potassium.

### Step 2: Calculate the mass ratio of potassium to bromine in KBr
From the information given, we know that potassium bromide (KBr) contains 32.9% potassium by mass. This means that:
- Mass of potassium in KBr = 32.9 g
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