Answer:
A. It is made up of only one substance
Explanation:
A) Molar mass gold ( Au) = 196.96 g/mol
1 mole Au ----------- 196.96 g
? moles Au ---------- 35.12 g
35.12 x 1 / 196.96
= 0.178 moles of Au
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b) 196.96 g --------------- 6.02x10²³ atoms
35.12 g ---------------- ( atoms ? )
35.12 x ( 6.02x10²³) / 196.96
2.114x10²⁵ / 196.96
= 1.07x10²³ atoms
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Answer:
The time decreases steadily
Explanation:
We know that the rate of chemical reaction is defined as how fast or slow a chemical reaction proceeds. Hence a chemical reaction is said to proceed at a faster rate if it takes a lesser time for the reaction to get to completion.
There are certain factors that affects the rate of reaction, prominent among them is the concentration of reactants. Concentration simply means the amount of substance in a system.
Taking a look at the table given in the question, we will realize that the volume of HCl remained constant, the volume of thiosulphate increased steadily while the volume of water decreased steadily. Remember that concentration increases when less water is added to the system. This implies that the reactant concentration increases steadily. Hence, according to the collision theory, particles collide more frequently and the rate of reaction increases.
As the rate of reaction increases, it now takes a lesser time for the reaction to get to completion (indicated by the disappearance of the cross). Hence as we move down the table, it takes lesser and lesser time for the cross to disappear. This means that the column for time will decrease steadily.
