These are reactions that take in energy from the surroundings (ie energy enters the reaction, which will help you to remember the name endothermic). The energy is usually transferred as heat energy, causing the reaction mixture and its surroundings to become colder.
<h3>
Answer:</h3>
70.906 g
<h3>
Explanation:</h3>
We are given;
- Atoms of Chlorine = 1.2 × 10^24 atoms
We are required to calculate the mass of Chlorine
- We know that 1 mole of an element contains atoms equivalent to the Avogadro's number, 6.022 × 10^23.
- That is , 1 mole of an element = 6.022 × 10^23 atoms
- Therefore; 1 mole of Chlorine = 6.022 × 10^23 atoms
But since Chlorine gas is a molecule;
- 1 mole of Chlorine gas = 2 × 6.022 × 10^23 atoms
But, molar mass of Chlorine gas = 70.906 g/mol
Then;
70.906 g Of chlorine gas = 2 × 6.022 × 10^23 atoms
= 1.20 × 10^24 atoms
Thus;
For 1.2 × 10^24 atoms ;
= ( 70.906 g/mol × 1.2 × 10^24 atoms ) ÷ (1.20 × 10^24 atoms)
<h3>= 70.906 g </h3>
Therefore, 1.20 × 10^24 atoms of chlorine contains a mass of 70.906 g
=
Answer:
5.96 g/cm^3
Explanation:
Corner atom = 1/8
Atoms in center = 1
Atoms in face of the cube= 1/2
Molar mass of V = 50.94 g/mol <em>(from period table)</em>
1 mole = 6.02x10^23
<em>In BCC unit cell:</em>
(8 x 1/8)+ 1=2 per 1 unit cell
<em>Mass: </em>2(50.94g)/6.02x10^23 = 1.69x10^-22 g/unit cell
305pm=(305x10^-12m÷10^-2m) x (1mL÷1cm^3)
= 2.837 x 10^-23 mL
<em>1pm=10^-12m</em>
<em>1cm=10^-2m</em>
<em>1mL=1cm^3</em>
<em></em>
density=mass/volume
density of V = 1.69x10^-22g÷2.837x10^-23mL
=5.957g/mL
=5.96g/cm^3
To covert from moles to atoms times the number of moles by Avogadro's Number (6.022×10²³)
4.0 × 6.022×10²³ = 2.4088×10^24
