5. How many grams of Br is needed to make 1000.g of a 2.0ppm solution?

2.0 × 10⁻³ g

Explanation:

Step 1: Given data

Step 2: Calculate the mass of Br₂ required to prepare the solution

The concentration of Br₂ is 2.0 ppm, that is, there are 2.0 mg of Br₂ per kilogram of solution. The mass of Br₂ required to prepare 1.000 kg of solution is:

1.000 kg Solution × 2.0 mg Br₂/1 kg Solution = 2.0 mg

Step 3: Convert the mass to grams

We will use the conversion factor 1 g = 1000 mg.

2.0 mg × 1 g/1000 mg = 2.0 × 10⁻³ g

in 1783 cavendish was working with his hydrogen gas and found that when he burned it and condensed the vapor it was water. this was very significant since it disproved the greek theory of elements completely since water was not a simple substance but the product of two gases. it was lavoisier who hearing of the experiment gave cavendish's gas the name hydrogen ("water-producer") and added that hydrogen burned by combining with oxygen and that water was a hydrogen-oxygen combination.

explanation: