Here's how to figure this out:
1. Know the atomic masses:
* Copper (Cu): 63.55 g/mol
* Chlorine (Cl): 35.45 g/mol
2. Assume a fixed amount of chlorine: Let's say we have 35.45 grams of chlorine (which is one mole).
3. Find the mass of copper that reacts with this chlorine:
* The most common copper chloride is copper(II) chloride (CuCl₂).
* The formula tells us that 1 mole of copper (63.55 g) reacts with 2 moles of chlorine (2 x 35.45 g = 70.9 g).
* To find the mass of copper that reacts with 35.45 g of chlorine, use a proportion:
(63.55 g Cu / 70.9 g Cl) = (x g Cu / 35.45 g Cl)
Solving for x: x = 31.775 g Cu
4. Find the simplest whole-number ratio:
* Cu: 31.775 g
* Cl: 35.45 g
* Divide both by the smaller value (31.775 g):
Cu: 1
Cl: 1.11
* The simplest whole-number ratio is approximately 1:1.
Therefore, the lowest whole-number mass ratio of copper to chlorine in copper(II) chloride is approximately 1:1.
Important Note: The actual ratio might be slightly different depending on the specific copper chloride compound. There are other possible copper chlorides (like copper(I) chloride, CuCl), which would have different mass ratios.
