C. Sn (tin) is a metal, Si (silicon) is a metalloid, and C (carbon) is a nonmetal
Explanation:
Atomic number is defined as the number of an element which represents total number of protons.
When an atom is neutral then it means it contains same number of protons and electrons.
On the other hand, atomic mass is defined as the sum of total number of protons and neutrons present in an atom.
Protons of every element remains fixed because it shows the identity of each element but if we change the number of neutrons then also identity of the atom will remain fixed. This is because changing the number of neutrons will not show any change in number of protons.
For example,
and
are isotopes of hydrogen and they have same number of protons but different number of neutrons.
Thus, we can conclude that number of neutrons can vary without changing the identity of the element.
Answer:
Density (ρ) = 5 kilogram/cubic meter
Explanation:
Steps:
ρ =
m
V
=
10 kilogram
2 cubic meter
= 5 kilogram/cubic meter
Answer: 0.20 M
Explanation:
According to the dilution law,

where,
= molarity of stock solution = 1.40 M
= volume of stock solution = 72.0 ml
= molarity of diluted solution = m
= volume of diluted solution = 248 ml


Now 124 mL portion of this prepared solution is diluted by adding 133 mL of water.
According to the dilution law,

where,
= molarity of stock solution = 0.41 M
= volume of stock solution = 124 ml
= molarity of diluted solution = m
= volume of diluted solution = (124 +133) ml = 257 ml


Thus the final concentration of the solution is 0.20 M.
696.32 mmHg is the final pressure of the gas.
<h3>What is an ideal gas equation?</h3>
The ideal gas equation, pV = nRT, is an equation used to calculate either the pressure, volume, temperature or number of moles of a gas.
Given data:
= 720 mmHg
= ?
= 2.5 mol
= 3.2 mol
= 34 L
= 45 L
Formula
Combined gas law

= 696.32 mmHg
Hence, 696.32 mmHg is the final pressure of the gas.
Learn more about an ideal gas equation here:
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