Webb has calculated the percent composition of a compound. How can he check his result?
1 answer:
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According to law of definite proportion:
In a compound, elements are always arranged in fixed ratio by mass.
Here, sample 1 has 23.22 g Carbon and 32.00 g Oxygen.
Converting mass into number of moles:
Molar mass of carbon is 12 g/mol and that of oxygen is 16 g/mol thus,
Similarly, number of moles of oxygen will be:
The ratio of number of moles of carbon and oxygen will be:
Therefore, formula of compound will be CO.
Sample 2:
It has 36.22 g Carbon and 48.00 g Oxygen.
Converting mass into number of moles:
Molar mass of carbon is 12 g/mol and that of oxygen is 16 g/mol thus,
Similarly, number of moles of oxygen will be:
The ratio of number of moles of carbon and oxygen will be:
The formula of compound will be CO.
Therefore, it is proved that carbon and oxygen are present in fixed ratios in both the samples.
Answer: The density of the material is 2.66 g/mL and it is likely this is made of Aluminum
Explanation:
The first step to know the material of the chunk of metal is to calculate its density. The general formula for density is P (density) = . Moreover, in this case, it is known the mass is 37.28 g, but the volume is not directly provided. However, we know the water in the graduated cylinder had a volume of 20.0 mL and this increased to 34.0 mL when the chunk of metal is added, this means the volume of the metal is 14 mL (34.0 mL - 20.0 mL = 14 mL). Now let's calculate the density:
This means the density of this metal is 2.66 g/mL, which can be rounded as 2. 7 g/mL, and according to the chart, this is the density of aluminum. Therefore, this material of this chunk is aluminum.