Answer:
when silver articles exposed to air silver racts with Sulphur present in the atmosphere and form a black layer of silver sulphide on the surface. copper articles get tarnished by reacting with air and water. due to this, a layer is formed over copper vessels.
<h3>
Answer:</h3>
= 5.79 × 10^19 molecules
<h3>
Explanation:</h3>
The molar mass of the compound is 312 g/mol
Mass of the compound is 30.0 mg equivalent to 0.030 g (1 g = 1000 mg)
We are required to calculate the number of molecules present
We will use the following steps;
<h3>Step 1: Calculate the number of moles of the compound </h3>

Therefore;
Moles of the compound will be;

= 9.615 × 10⁻5 mole
<h3>Step 2: Calculate the number of molecules present </h3>
Using the Avogadro's constant, 6.022 × 10^23
1 mole of a compound contains 6.022 × 10^23 molecules
Therefore;
9.615 × 10⁻5 moles of the compound will have ;
= 9.615 × 10⁻5 moles × 6.022 × 10^23 molecules
= 5.79 × 10^19 molecules
Therefore the compound contains 5.79 × 10^19 molecules
Definitely Calcium Chloride.
All the others are covalent.
<span>Grams of solute per 100 grams of water</span>
Answer:
1. Balanced chemical for the given chemical reaction is :

number of mole of sulphuric acid produced = 12.5 mol
number of mole of oxygen required=6.25 mol
Explanation:
1. Balanced chemical for the given chemical reaction is :

from above balanced equation it is clearly that ,
2 mole of sulpher dioxide gives 2 mole of sulphuric acid
1 mole of sulpher dioxide gives 1 mole of sulphuric acid
therefore,
12 .5 mole of sulpher dioxide will givs 12.5 mole of sulphuric acid
number of mole of sulphuric acid produced = 12.5 mol
2 mole of sulphur dioxide needs 1 mole of oxygen gas
so,
1 mole of sulphur dioxide needs 0.5 mole of oxygen gas
therefore 12.5 of sulphur dioxide needs
mole of oxygen
number of mole of oxygen required=6.25 mol