<u>Answer:</u>
<em>B. A and B</em>
<em></em>
<u>Explanation:</u>
1. Solids have a definite volume, definite size and definite shape
2. The particles present in a solid are very closely packed since the intermolecular forces between them are very strong. The molecules do not move apart.
3. Melting point is the temperature at which solid changes into a liquid.
4. When a solid is heated to the melting point the intermolecular forces are overcome by the energy and the molecules present in it moves from its fixed position to take its liquid state which is called as melting.
The number of H atoms in 3(NH₄)₂CrO₄ = 24
<h3>Further explanation </h3>
The empirical formula is the smallest comparison of atoms of compound forming elements.
A molecular formula is a formula that shows the number of atomic elements that make up a compound.
(empirical formula) n = molecular formula
Subscripts in the chemical formula indicate the number of atoms
The compound of 3(NH₄)₂CrO₄ ( 3 molecules of (NH₄)₂CrO₄ ) :
Number of H :

First of all, this is the chemistry section, while your question is a physics question. Anyway I'll tell you how to solve it.
First we need to find the rate that the truck moves in a second.
1km = 1000m
40km = 40000m
40000m/hr
1 hour = 60 minutes
40000m/hr ÷ 60 = 666.66(repeating)/minute
1 minute = 60 seconds
666.66m/min ÷ 60 = 11.11(rep)m/s
Next we simply multiply the speed of the truck by the number of seconds it travels.
11.11 × 5 = 55.55
Make sure to round it unless you indicate the repeating decimal.
The truck moved 55.56m in 5 seconds.
It is softer than topaz and and it is softer than diamond (diamond has a Mohs hardness of 10, which is the highest value of the scale)