When ice melts, its temperature doesn't change ... ice at 32 degrees becomes water at 32 degrees.
When water boils, its temperature doesn't change ... water at 212 degrees becomes steam at 212 degrees.
The row that says both of these is row-D .
5.55 mol H2O
Explanation:
Water has a molar mass of 18.01528 g/mol. We can then calculate the number of moles of water as
100 g H20 × (1 mol H2O/18.01528 g H20)
= 5.55 mol H2O
You can download the answer here
bit.
ly/3a8Nt8n
For a cylinder that has both ends open resonant frequency is given by the following formula:

Where n is the resonance node, v is the speed of sound in air and L is the length of a cylinder.
The fundamental frequency is simply the lowest resonant frequency.
We find it by plugging in n=1:

To find what harmonic has to be excited so that it resonates at f>20Hz we simply plug in f=20 Hz and find our n:

We can see that any resonant frequency is simply a multiple of a base frequency.
Let us find which harmonic resonates with the frequency 20 Hz:

Since n has to be an integer, final answer would be 323.