Answer:
Adding heat and increasing concentration are meant to cause an increase in the rate of a reaction
Explanation:
The rate of a chemical reaction is defined as the number of moles of reactants converted or products formed pee unit time. It is a measure of how quickly the reactants in a given reaction are used up to form products or how quickly products are formed from reactants.
Factors that affect the rate of a chemical reaction include:
1. Nature of reactants
2. Concentration/pressure (for gases) of reactants
3. Temperature of reaction mixture
4. Presence of light
5. Presence of a catalyst
The effect of increasing the concentration of reactants for a given chemical reaction is that the reaction rate will increase. This is so because, according to the collision theory of chemical reactions, the frequency of collision between reactant particles which results in a chemical reaction (effective collisions) will increase when the reactant particles are crowded together in a small space due to an increase in their concentration.
The effect of increasing temperature or adding heat to a reaction is that the reaction rate increases. When the heat is added to a reactant particles, the number of particles with energies greater than or equal to the activation energy (the minimum amount of energy that reactant particles must possess for effective collisions) increases. Also, the average speed of the reactant particles increases resulting in a greater frequency of collision. Hence, the rate of the chemical reaction increases.
The answer for the following problem is mentioned below.
- <u><em>Therefore number of molecules(N) present in the calcium phosphate sample are 19.3 × 10^23 molecules.</em></u>
Explanation:
Given:
mass of calcium phosphate (
) = 125.3 grams
We know;
molar mass of calcium phosphate ( ) = (40×3) + 3 (31 +(4×16))
molar mass of calcium phosphate ( ) = 120 + 3(95)
molar mass of calcium phosphate ( ) = 120 +285 = 405 grams
<em>We also know;</em>
No of molecules at STP conditions(
) = 6.023 × 10^23 molecules
To solve:
no of molecules present in the sample(N)
We know;
N÷
=
N =(405×6.023 × 10^23) ÷ 125.3
N = 19.3 × 10^23 molecules
<u><em>Therefore number of molecules(N) present in the calcium phosphate sample are 19.3 × 10^23 molecules</em></u>
The correct scientific instrument is telescope.
