1) A. the have different protons.
The number of protons is the atomic number and this is how the products are ordered in the periodic table. Every element has different atomic number.
2) A. 8 p, 8 e and 8 n
The atomic number of O is 8, which means it has 8 protons. The number of protons must equal the number of electrons.
3) C. atoms bond with one another in a molecule.
That is what a molecule is: a group ot atoms bonded.
4) D. the bond results from the attractive forces of two opposite charges.
Ionic bonds are formed between ions, a positive ion (cation) and a negative ion (anion).
5) A. the physical and chemical properties of HCl are different from those of H2 and Cl2
You can check physical properties (density for example) and chemical properties (how they react with other elements) in some tables o textbooks.
Explanation:
I don't understand the question
Answer: 46.5 kJ
Explanation:
The balanced chemical reaction is:


given mass = 11.1 g
Molar mass = 44.01 g/mol

0.252 moles of carbon dioxide react with sufficient hydrogen, energy released = 5.86 kJ
2 moles of carbon dioxide react with sufficient hydrogen, energy released =
Thus value of ΔHrxn for the chemical equation given is 46.5 kJ