Answer:
This is due the different charges of fluoride and oxide ions.
Explanation:
When calcium reacts it is oxidized to Ca²⁺. In the same way, fluoride ion is reduced to F⁻ and oxide ion to O²⁻.
When these ions are combined, the molecule must be neutral. That means 2 ions of F⁻ are necessaries and just 1 O²⁻ ion will reacts producing:
CaF₂ and CaO.
The different charges of these ions is the reason why calcium will combine in different ratios.
Answer:
Option B. A
Explanation:
From the question given above, the following data were obtained:
C(s) + 2H₂ (g) —> CH₄ (g). ΔH = –74.9 kJ
From the reaction above, we can see that the enthalpy change (ΔH) is negative (i.e –74.9 KJ) which implies that the heat content of the reactants is greater than the heat content of the products. Thus, the reaction is exothermic reaction.
For an exothermic reaction, the energy profile diagram is drawn in such a way that the heat content of reactants is higher than the heat content of products because the enthalpy change
(ΔH) is always negative.
Thus, diagram A (i.e option B) gives the correct answer to the question.
As we know that,
1 mm Hg = 1 torr
So,
745 mm Hg = X
X = (745 mm Hg × 1 torr) ÷ 1 mm Hg
X = 745 torr
Also,
1 mm Hg = 133.325 Pa
So,
745 mm Hg = X
X = (745 mm Hg × 133.325 Pa) ÷ 1 mm Hg
X = 99327 Pa
Result:
Option-A (745 torr) is the correct answer.
Answer:
The answer to your question is below
Explanation:
1.-
a) Look for the mass number of Gold in the periodic table
Mass number = 197 g
Use proportions to answer this question
197 g of gold ------------- 6.023 x 10 ²³ atoms
4.64 g of gold ---------- x
x = (4.64 x 6.023 x 10²³) / 197
x = 1.42 x 10²² atoms
2.- mass of 4.12 x 10²⁴ molecules of glucose
Molecular mass = (6 x 12) + (12 X 1) + (6 x 16)
= 72 + 12 + 96
= 180 g
180 g of glucose ------------------- 6.023 x 10 ²³ molecules
x ------------------- 4.12 x 10 ²⁴ molecules
x = (4.12 x 10²⁴ x 180) / 6.023 x 10²³
x = 1231.3 g of glucose
Answer:
Explanation:
Iron Haber process = (making ammonia)
Vanadium (V) oxide = Contact process (a stage in making sulfuric acid)
Manganese dioxide = Decomposition of hydrogen peroxide (produces water and oxygen)
