Answer: the sum of the partial pressures of the individual gases.
Explanation:
According to Dalton's Law of partial pressure, the total pressure of a mixture of gases is equal to the sum of the partial pressures which each individual gas would exert if it were confined alone in the volume occupied by the mixture.
Hence, Ptotal = P1+ P2
where Ptotal is the total pressure
P1 and P2 are the partial pressures exerted seperately by the individual gases 1 and 2 that make up the mixture.
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.
