Answer:
A. N₂(g) + 3H₂(g) -----> 2NH₃ exothermic
B. S(g) + O₂(g) --------> SO₂(g) exothermic
C. 2H₂O(g) --------> 2H₂(g) + O₂(g) endothermic
D. 2F(g) ---------> F₂(g) exothermic
Explanation:
The question says predict not calculate. So you have to use your chemistry knowledge, experience and intuition.
A. N₂(g) + 3H₂(g) -----> 2NH₃ is exothermic because the Haber process gives out energy
B. S(g) + O₂(g) --------> SO₂(g) is exothermic because it is a combustion. The majority, if not all, combustion give out energy.
C. 2H₂O(g) --------> 2H₂(g) + O₂(g) is endothermic because it is the reverse reaction of the combustion of hydrogen. If the reverse reaction is exothermic then the forward reaction is endothermic
D. 2F(g) ---------> F₂(g) is exothermic because the backward reaction is endothermic. Atomisation is always an endothermic reaction so the forward reaction is exothermic
We call it a solid because it has the () and in s inside of it meaning solid
Answer:
1.2×10²³ atoms.
Explanation:
Data obtained from the question include:
Mole of propanone = 0.20 mole
Number of atoms of propanone =.?
From Avogadro's hypothesis, we understood that 1 mole of any substance contains 6.022×10²³ atoms.
This implies that 1 mole of propanone also contains 6.022×10²³ atoms.
Thus, we can obtain the number of atoms in 0.20 mole of propanone as illustrated below:
1 mole of propanone contains 6.022×10²³ atoms.
Therefore, 0.20 mole of propanone will contain = 0.2 × 6.022×10²³ = 1.2×10²³ atoms.
Thus, 0.20 mole of propanone contain
1.2×10²³ atoms.
Molarity is defined as the number of moles of solute in 1 L of solution
the mass of Ca(NO₃)₂ present - 8.50 g
therefore number of moles of Ca(NO₃)₂ - 8.50 g / 164 g/mol = 0.0518 mol
the volume of solution prepared is 755 mL
therefore if there are 0.0518 mol in 755 mL
then in 1000 mL the number of moles - 0.0518 mol / 0.755 L
molarity is therefore - 0.0686 M
