Answer:
A - NaCl is a product
D - Cl2 is a gas
Explanation:
Based on the chemical reaction;
2Na(s) + Cl2(g) → 2NaCl2
- Sodium metal reacts with chlorine gas to form sodium chloride. Sodium is in solid state, chlorine is in gaseous state and Sodium chloride is in solid state.
- In the chemical reaction, sodium and chlorine are reactants while sodium chloride is the product.
- Additionally the chemical reaction above is balanced so as to obey the law of conservation of mass.
Answer:
Amount left after 25 days = 12.5 g
Explanation:
Given data:
Mass of sample = 400 g
Half life of sample = 5 days
Mass left after 25 days = ?
Solution:
First of all we will calculate the number of half lives passes in given time period.
Number of half lives = Time elapsed / Half life
Number of half lives = 25 days/ 5 days
Number of half lives = 5
At time zero = 400 g
At 1st half life = 400 g/2 = 200 g
At 2nd half life = 200 g/2 = 100 g
At 3rd half life = 100 g/2 = 50 g
At 4th half life = 50 g/2 = 25 g
At 5th half life = 25 g/2 = 12.5 g
Answer:
0.57 water
Explanation:
To solve this problem, we need to write the reaction expression first.
The reactants are oxygen gas and hydrogen gas.
They react to give a product of water
2H₂ + O₂ → 2 H₂O
Given that;
Number of moles of hydrogen gas = 0.57moles
From the balanced reaction expression;
2 moles of hydrogen gas produces 2 moles of water
So;
0.57mole of hydrogen gas will also produce 0.57 water
Answer: <span>O₂(g), Br₂(l) Fe(s), He(g)
</span>
Justification:
1) The state variable given, ΔHf°, is <span>the standard
enthalpy of formation. By definition it is the change in the enthalpy that accompanies the
formation of a mole of compound in the standard state, from its
constituent elements in the standard state.
</span>
2) Since the standard state of <span>O₂(g), Br₂(l) Fe(s), He(g) is the very same shown, they do not evolve any heat for its formation. This is, that is the same state of the constituents, and no change is involved.
</span>
<span>That is why, </span><span>ΔHf°, of those elements is 0.
</span>
Answer: 6 valence electrons
Explanation: the valence electrons and group are always the same, but when the group numbers are 10 and above, they would be the first number. For example, every element in group 16 has 6 valence electrons.
