Answer:
at first i would like to tell which class
Explanation:
125000 is the answwr
Answer: The correct option is The properties of a noble gas.
Explanation: There are 7 periods in the periodic table.
The last element of each period are Helium (He), Neon (Ne), Argon (Ar), Krypton (Kr), Xenon (Xe), Radon (Rn) and Ununoctium (Uuo).
- The electronic configuration for Helium is
. For He, The outermost electrons are 2.
- The electronic configuration for all the other elements is
( where, n = 2, 3, 4, 5, 6 and 7 respectively). For all the other gases, the outermost electrons are 8.
All these elements have stable electronic configuration and are not reactive in nature. Hence, they are considered as noble gases.
Therefore, the last element of each period always have the properties of a noble gas.
<span>The density of the solution =1.05 g/ml.
</span><span>The total mass of the resulting solution is = 398.7 g (CaCl2 + water)
</span>
Find moles of CaCl2 and water.
Molar mass of CaCl2 = 110 (approx.)
Moles of CaCl2 = 23.7 / 110 = 0.22
so, moles of Cl- ion = 2 x 0.22 = 0.44 (because each molecule of CaCl2 will give two Cl- ions)
Moles of water = 375 / 18 = 20.83
Now, Mole fraction of CaCl2 = (moles of CaCl2) / (total moles)
total moles = moles of Cl- ions + moles of Ca2+ ions + moles of water
= 0.44 + 0.22 + 20.83
=21.49
So, mole fraction = 0.44 / (21.49) = 0.02
Guess what !!! density is not used. No need
Answer:
7.224 × 10^28 atoms
Explanation:
The number of moles contained in a substance (n) can be calculated from this expression:
nA = n × 6.02 × 10^23 atoms
Where;
nA = number of atoms of substance
n = number of moles of substance
Avagadro's number or constant = 6.02 × 10^23 atoms
Using nA = n × 6.02 × 10^23 atoms
In this question, there are 1.2 x 10^5 moles of neon (N). The number of atoms (nA) is as follows:
nA of neon = 1.2 x 10^5 × 6.02 × 10^23
nA = 7.224 × 10^ (5 + 23)
nA = 7.224 × 10^28 atoms
The number of neon atoms in 1.2 x 10^5 is 7.224 × 10^28 atoms.
