Explanation:
Atomic mass means the sum of total number of protons and neutrons present in an atom.
When an atom is neutral then number of protons equal the number of electrons.
Mass of a proton equals to 1.007276 u, mass of neutron equals to 1.008664 u.
For example, in a 
atom there are total 9 protons and number of neutrons is 19 - 9 = 10.
Since, it is a neutral atom so number of electrons will also be 9.
So, total mass will be calculated as follows.
Total mass = 9 (mass of electron + mass of proton)
= 9 (1.007825 u)
= 9.07043 u
Therefore, we can conclude that total mass of protons and electrons in is 9.07043 u.
Answer:
Choice B. The solid with hydrogen bonding.
Assumption: the molecules in the four choices are of similar sizes.
Explanation:
Molecules in a molecular solid are held intact with intermolecular forces. To melt the solid, it is necessary to overcome these forces. The stronger the intermolecular forces, the more energy will be required to overcome these attractions and melt the solid. That corresponds to a high melting point.
For molecules of similar sizes,
- The strength of hydrogen bonding will be stronger than the strength of dipole-dipole attractions.
- The strength of dipole-dipole attractions (also known as permanent dipole) will be stronger than the strength of the induced dipole attractions (also known as London Dispersion Forces.)
That is:
Strength of Hydrogen bond > Strength of Dipole-dipole attractions > Strength of Induced dipole attractions.
Accordingly,
Melting point due to Hydrogen bond > Melting point due to Dipole-dipole attractions > Melting point due to Induced Dipole attractions.
- Induced dipole is possible between all molecules.
- Dipole-dipole force is possible only between polar molecules.
- Hydrogen bonds are possible only in molecules that contain
atoms that are bonded directly to atoms of 
, 
, or 
.
As a result, induced dipoles are the only force possible between molecules of the solid in choice C. Assume that the molecules are of similar sizes, such that the strengths of induced dipole are similar for these molecules.
Melting point in choice B > Melting point in choice D > Melting point in choice A and C.
Answer : Option 2) Nonmetallic properties and ionization energy
Explanation : It is observed that the nonmetallic properties and the ionization energy when the elements in period 3 on the periodic table are considered in order from left to right.
Various changes are observed when we move from left to right in period 3 in the modern periodic table like the atomic number and charge on the nucleus increases
, number of valence electrons increases
, atomic radius decreases
, first ionization energy increases
, electro negativity increases except in Ar, elements found on the left are metals and elements on the right are non-metals, so non metallic character increases.
The granite block transferred <u>4080 J</u> of energy, and the mass of the water is <u>35.8 g</u>.
1. <em>Energy from granite block
</em>
The formula for the heat (<em>q</em>) transferred is
<em>q = mC</em>Δ<em>T</em>
<em>m</em> = 126.1 g; <em>C</em> = 0.795 J·°C⁻¹g⁻¹; Δ<em>T</em> = <em>T</em>_f – <em>T</em>_i = 51.9 °C - 92.6 °C = -40.7 °C
∴ <em>q</em> = 126.1 g × 0.795 J·°C⁻¹g⁻¹ × (-40.7 °C) = -4080 J
The granite block transferred 4080 J.
2. <em>Mass of water
</em>
<em>q = mC</em>Δ<em>T
</em>
<em>m = q</em>/(<em>C</em>Δ<em>T</em>)
<em>q </em>= 4080 J; <em>C</em> = 4.186 J·°C⁻¹g⁻¹; Δ<em>T</em> = <em>T</em>_f – <em>T</em>_i = 51.9 °C – 24.7 °C = 27.2 °C
∴ <em>m</em> = 4080 J/(4.186 J·°C⁻¹g⁻¹ × 27.2 °C) = 35.8 g
The mass of the water is 35.8 g.
