Answer:
1) B. The change in energy in a system during an exothermir reaction
2) B. In the air, only the oxygen is part of the system
3) B. The energy found in the reactants....
4) D. This is an endothermic reaction because the system took energy from the surroundings.
5) B. Energy is released by the formation of chemical bonds
Explanation:
TOOK THE QUIZ...YOU'RE WELCOME!!!
Answer:
I hope this answers the question
Explanation:
The amount of grams of hydrogen that are in the water sample is;
3.985 g
<h3>Avogadro's number</h3>
We are given that;
Number of moles of oxygen in a sample of water = 12 × 10²³
- Now, the chemical formula of a molecule of water is H₂O. This means that for every 1 atom or molecule of oxygen, there must be 2 hydrogen atoms or molecules present.
Since Number of moles of oxygen in the sample is 12 × 10²³, then number of moles of hydrogen will be twice that = 2 × 12 × 10²³ = 24 × 10²³ moles
Now, molar mass of hydrogen is 1 g/mol and we know that;
Molar mass = Avogadro's number(6.023 × 10²³) moles
Thus;
6.023 × 10²³ moles = 1 g/mol
Thus; 24 × 10²³ moles of hydrogen = ( 24 × 10²³ × 1)/(6.023 × 10²³)
⇒ 3.985 g
Read more on Avogadro's number at; brainly.com/question/914267
