Answer:
The time taken for the cross to become invisible decreases.
Explanation:
We know that one of the factors affecting the rate of reaction is the concentration of reactants. From the collision theory, we know that the higher the concentration of reactants, the greater the possibility of effective collision between reactants leading ultimately to an increase in the rate of reaction. Increase in the rate of reaction implies that the reaction takes a shorter time to reach completion.
In the case of the reaction shown in the question, the point when the reaction is completed is observed by the time take for the cross mark to become invisible. If we look at the given data closely, we will notice that the volume of acid was held constant, the volume of thiosulphate was increased gradually while the volume of water was decreased accordingly. This implies that the concentration of the reactants was increased. Decreasing the volume of water increases reactant concentration.
As explained above, increase in reactant concentration increases the rate of reaction. Hence, the rate of reaction of the acid and thiosulphate increases as reactant concentration increases and the cross mark becomes invisible faster. This implies that in the last column for time taken for the cross to become invisible, the values of time decreases steadily as concentration of reactants increases.
Answer:
<u>Balanced equation:</u>

Explanation:
The chemical reaction between Lead(II) Nitrate and potassium carbonate is as follows.


<u>Ionic equation:</u>

Cancel the same ions on the both sides of the reaction.
The net ionic equation is as follows.

Answer:
D is the answer to this problem
<u>Answer:</u>
<em>The situation given here is imaginary such that the life of Rock has to be found using the half-life of the element lokium that has been found inside the rock. </em>
<u>Explanation:</u>
Half-life of any material is the amount of time taken by that particular material to decay. Now the amount of lokium found in rock can show after how many half-lives this amount has been left out.
The time elapsed will be log (L) atoms X half-life.
I think the best answer is the last option. A scatter plot is the appropriate type of graph for the student to use to show the percent samples per group. This plot is somewhat similar to line graphs. However, they are use for a specific purpose which is to show the relationship between two parameters. In this case, the correlation between pH and the percent of samples.