Answer:
162 g Fe₂O₃
Explanation:
To find the mass of Fe₂O₃, you need to (1) convert grams C to moles C (via molar mass from periodic table), then (2) convert moles C to moles Fe₂O₃ (via mole-to-mole ratio from reaction coefficients), and then (3) convert moles Fe₂O₃ to grams (via molar mass). It is important to arrange the ratios/conversions in a way that allows for the cancellation of units. The final answer should have 3 sig figs to reflect the given value.
Molar Mass (C): 12.011 g/mol
2 Fe₂O₃(s) + 3 C(s) ---> 4 Fe(s) + 3 CO₂(g)
Molar Mass (Fe₂O₃): 2(55.845 g/mol) + 3(15.998 g/mol)
Molar Mass (Fe₂O₃): 159.684 g/mol
18.3 g C 1 mole 2 moles Fe₂O₃ 159.684 g
-------------- x ---------------- x ------------------------- x ----------------- = 162 g Fe₂O₃
12.011 g 3 moles C 1 mole
There's no reason, it's just because the sun has a gravitational pull
A). 4
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The number 345,000 has 3 significant figures because the trailing zeros are not significant since there's no decimal point.
<h3>What is significant figures?</h3>
Significant figures of a number in positional notation are digits in the number that are reliable and necessary to indicate the quantity of something.
Also significant figures can be defined as, the number of digits in a value, often a measurement, that contribute to the degree of accuracy of the value.
Examples of significant figures;
- 405 = 3 significant figures
- 405000 = 3 significant
- 0.040500 = 5 significant figures
<u>Note:</u> leading zeros are not significant but trailing zeros, which are zeros at the end of a number, are significant only if the number has a decimal point.
345,000 = 3.45 x 10⁵ (3 significant figures)
Thus, the number 345,000 has 3 significant figures because the trailing zeros are not significant since there's no decimal point.
Learn more about significant figures here: brainly.com/question/24491627
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To calculate the concentration of the base based on the titration, the concept used is the equal of number of equivalence of the acid used to that of the base. From this,
Na x Va = Nb x Vb
For HBr and KOH, molarity is equal to normality. Substituting the known values,
(0.75 M) x (22.6 mL - 0 mL) = Nb x (37.5 mL - 0.5 mL)
Nb = 0.46 N
Mb = 0.46 M
Thus, the concentration of the base is approximately 0.46 M.