Scientists use scientific notation to communicate extremely small measurements. Hence, option A is correct.
<h3>What scientific notation?</h3>
Scientific notation is a way of writing very large or very small numbers.
Scientists use scientific notation to represent very small or very large numbers because this notation increases the
- accuracy of measured quantities.
- convenience in using the numbers.
- the number of significant figures.
- precision of measurements.
Hence, option A is correct.
Learn more about the scientific notation here:
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Convert the amount of substance in carat to grams.
(5.0 carat) x (0.200 g / 1 carat) = 1 g
The volume of the substance is obtained by dividing the mass by the density,
v = m / d
v = 1 g / (3.51 g/cm³) = 0.2849 cm³
Therefore, the volume of a 5.0 carat diamond is approximately 0.285 cm³.
Answer:
The answer to your question is: ΔHrxm = -23.9 kJ
Explanation:
Data:
2Fe(s)+3/2O2(g)→Fe2O3(s), ΔH = -824.2 kJ (1)
CO(g)+1/2O2(g)→CO2(g) ΔH = -282.7 kJ (2)
Reaction:
Fe2O3(s)+3CO(g)→2Fe(s)+3CO2(g)
We invert (1) and change the sign of ΔH
Fe2O3(s) → 2Fe(s)+3/2O2(g) ΔH = 824.2 kJ
We multiply (2) by 3
3( CO(g)+1/2O2(g)→CO2(g) ΔH = -282.7 kJ) (2)
3CO(g)+3/2O2(g)→3CO2(g) ΔH = -848.1 kJ
We add (1) and (2)
Fe2O3(s) → 2Fe(s)+3/2O2(g) ΔH = 824.2 kJ
3CO(g)+3/2O2(g)→3CO2(g) ΔH = -848.1 kJ
Fe2O3(s) + 3CO(g)+3/2O2(g) → 2Fe(s)+3/2O2 + 3CO2(g)
Simplify
Fe2O3(s)+3CO(g)→2Fe(s)+3CO2(g) and ΔHrxm = -23.9 kJ
