58.7 %
Please correct me if I’m wrong. :)
Answer: 72 grams of
are needed to completely burn 19.7 g 
Explanation:
According to avogadro's law, 1 mole of every substance weighs equal to molecular mass and contains avogadro's number
of particles.
To calculate the number of moles, we use the equation:

Putting in the values we get:


According to stoichiometry:
1 mole of
requires 5 moles of oxygen
0.45 moles of
require=
moles of oxygen
Mass of 
72 grams of
are needed to completely burn 19.7 g 
Answer:
The solubility of the mineral compound X in the water sample is 0.0189 g/mL.
Explanation:
Step 1: Given data
The volume of water sample = 46.0 mL.
The weight of the mineral compound X after evaporation, drying, and washing = 0.87 g.
Step 2: Calculate the solubility of X in water
46.00 mL of water sample contains 0.87 g of the mineral compound X.
To calulate how many grams of the mineral compound 1.0 mL of water sample contains:
0.87 g/46.0 mL = 0.0189 g.
This means the solubility of the mineral compound X in the water sample is 0.0189 g/mL.
Answer:
The solute is the substance being dissolved.
The solvent is the substance dissolving the solute.
Therefore, the salt is the solute and the water is the solvent.
Explanation:
The salt is the solute.
b. increase in surface area
<h3>Further explanation</h3>
Given
Speeding up a chemical reaction
Required
Factors used to speed up reactions
Solution
There are several factors that influence reaction kinetics :
1. Concentration
2. Surface area
3. Temperature
4. Catalyst
5. Pressure
6. Stirring
Temperature is related to the kinetic energy of the particles. Heat is absorbed causes the particles of matter to move faster so that the reaction can take place faster
The enlarged surface area of the reactants causes more particles to react with other particles.
50 g square block of sulfur can be broken into small pieces or powdered so that more particles come into contact with each other