How many grams of chloride ions are in 8.3 g of copper (ii) chloride

2.4 grams.

Explanation

Refer to a modern periodic table for relative atomic mass:

Cu- 63.546;Cl- 35.45.

Formula of copper (II) chloride: CuCl₂.

Formula mass of copper (II) chloride:

63.546 + 2 × 35.45 = 240.796 g / mol.

How many moles of formula units in 8.3 grams of CuCl₂?

8.3 / 240.796 = 0.0345 moles.

Note the subscript "2" in the formula CuCl₂. There are two moles of chloride ions in each formula unit of CuCl₂.

There are 2 × 0.0345 = 0.0689 moles of Cl ions in 0.0345 moles formula units of CuCl₂.

The mass of one mole of chloride ion is 35.45 grams.

The mass of 0.0689 moles of chloride ions will be 35.45 × 0.0689 = 2.4 grams.

Round the final value to two sig. fig. since the mass in the question is also 2 sig. fig.

Explanation:

Density is defined as the mass of the substance present in the unit volume of the substance.

When a substance is immersed in the liquid with density greater than that of the substance. Then the substance will float on the liquid.When a substance is immersed in the liquid with density lower than that of the substance. Then the substance will sink in the liquid

So, when the rock is immersed in the water the it sank because the density if the rock is greater than the density of water.

Where as wooden block float in the water because the density of the wooden block is less then the density of the water.