K because parent atoms are always larger than their cations(positively charged atoms)
Radioactive material obeys 1st order decay kinetics,
For 1st order reaction, we have
k =

where, k = rate constant of reaction
Given: Initial conc. 100, Final conc. = 6.25, t = 18.9 hours
∴ k =

= 0.1467 hours^(-1)
Now, for 1st order reactions: half life =

= 4.723 hours.
Hello!
Bromine can be classified as a pure substance.
Why?
Bromine is an element with atomic number 35 on group 17 of the Periodic Table. That's the first sign that shows us that it is a pure substance.
But the fact that it has a clear and defined boiling and melting point is a sign that we are in the presence of a pure substance. Pure substances are characterized by defined boiling and melting points.
Mixtures usually have a range of temperatures in which they melt and boil.
Have a nice day!
<h3>
Answer:</h3>
0.89 J/g°C
<h3>
Explanation:</h3>
Concept tested: Quantity of heat
We are given;
- Mass of the aluminium sample is 120 g
- Quantity of heat absorbed by aluminium sample is 9612 g
- Change in temperature, ΔT = 115°C - 25°C
= 90°C
We are required to calculate the specific heat capacity;
- We need to know that the quantity of heat absorbed is calculated by the product of mass, specific heat capacity and change in temperature.
That is;
Q = m × c × ΔT
- Therefore, rearranging the formula we can calculate the specific heat capacity of Aluminium.
Specific heat capacity, c = Q ÷ mΔT
= 9612 J ÷ (120 g × 90°C)
= 0.89 J/g°C
Therefore, the specific heat capacity of Aluminium is 0.89 J/g°C
A mirror is opaque, meaning that it reflects the light and images that shine on it's reflective surface.