<span><span>Number of Protons-19 </span><span>Number of Neutrons-20 </span><span>Number of Electrons-<span>19</span></span></span>
Answer:
The density of acetic acid at 30°C = 1.0354_g/mL
Explanation:
specific gravity of acetic acid = (Density of acetic acid at 30°C) ÷ (Density of water at 30°C)
Therefore, the density of acetic acid at 30°C = (Density of water at 30°C) × (Specific gravity of acetic acid at 30°C)
= 0.9956 g/mL × 1.040
= 1.0354_g/mL
Specific gravity, which is also known as relative density, is the ratio of the density of a substance to the density of a specified standard substance.
Generally the standard substance of to which other solid and liquid substances are compared is water which has a density of 1.0 kg per litre or 62.4 pounds/cubic foot at 4 °C (39.2 °F) while gases are normally compared with dry air, with a density of 1.29 grams/litre or 1.29 ounces/cubic foot under standard conditions of a temperature of 0 °C and one standard atmospheric pressure
Metallic bonding
Metals consist of giant structures of atoms arranged in a regular pattern. The electrons from the outer shells of the metal atoms are delocalised , and are free to move through the whole structure. This sharing of delocalised electrons results in strong metallic bonding .
Answer:
The element will be 
Explanation:
Given that,
Number of proton = 80
Number of neutron = 81
Number of electron = 79
We know that,
The atomic number is equal to the number of proton.
So, the atomic number is 80.
According to atomic number,
The element will be mercury.
We need to calculate the atomic mass
Using formula of atomic mass

Put the value into the formula


We need to find the element
Using atomic mass and atomic number


So, the element will be

Put the value of A and Z
Hence, The element will be 
The pressure of diver = atmospheric pressure + water pressure
atmospheric pressure = 750 mmHg (as given) = 750 / 760 atm = 0.987 atm
Water pressure is
P = hρg
where
h = height of water = 38 ft
1 ft = 0.3048
38 ft = 11.58 m
ρ = density = 1000 Kg / m³
g = gravitational constant = 9.81 m/s2
P = 11.58 X 1000 X 9.81 = 113599.8 Kg / m s^2 Or N /m^2
1 N / m^2 = 1 pa = 9.869 X 10^-6 atm
P = 113599.8 Pa = 1.12 atm
Total pressure = 1.12 + 0.987 atm = 2.107 atm = 2.1 atm (two significant figures)