Answer : The time required for decay is, 84 days.
Explanation :
Half-life of chromium-51 = 28 days
First we have to calculate the rate constant, we use the formula :
Now we have to calculate the time required for decay.
Expression for rate law for first order kinetics is given by:
where,
k = rate constant
t = time taken by sample = ?
a = let initial activity of the sample = 100
a - x = amount left after decay process = 12.5
Now put all the given values in above equation, we get
Therefore, the time required for decay is, 84 days.
Answer:
D) N-Cl.
Explanation:
The electronegativity of the elements in Group 5 (N. P As and Bi) decreases as we go down the Group so N is the most electronegative and chlorine is less able to draw electrons away from N than from the other elements in Group 5.
Answer:
After the solution is heated, but before additional solute is added
Explanation:
An unsaturated solution is a solution that contains less solute than it can normally hold at a given temperature. Hence an unsaturated solution can still dissolve more solute.
When the solution is heated, the saturated cold solution becomes an unsaturated hot solution which is capable of dissolving more solute at this point.
Once more solute is dissolved, the solution becomes saturated again just before it begins to cool since no more solute dissolves in the solution at some point before cooling and addition of seed crystals.
Answer:
True
Explanation:
If a question cannot be tested and observed, it cannot simply be answered by science.
Science works with observable and testable ideas and not on metaphysics.
- Science presents a methodical approach into investigating phenomenon and answering likely questions in a logical manner.
- The body of facts and data gathered through observations and tests are used to ramify the conclusion of a scientific study.
- Without such, it is impossible to do the work of science.
Answer:
The solvent is the substance that dissolves solutes.
Explanation:
Solutes are the ones being dissolved. Examples could be sugar, salt, etc.
Solvents are the dissolver. Examples could be acids like HCl or water.
