An athlete preparing for a marathon runs 21.3 miles. How many kilometers did they run? (please give fourmula)
1 answer:
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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.
Answer: 51.45 grams of excess reagent is left after the completion of reaction.
Explanation: For the calculation of moles, we use the formula:
....(1)
- For Si
Given mass = 92 grams
Molar mass = 28g/mol
Putting values in equation 1, we get:
- For
Given mass = 112 grams
Molar mass = 116g/mol
Putting values in equation 1, we get:
The reaction follows:
By Stoichiometry,
2 moles of reacts with 3 moles of silicon
So, 0.965 moles of reacts with =
= 1.4475 moles of Silicon.
As, the moles of silicon is more than the required amount and is present in excess.
So, the excess reagent for the reaction is Silicon.
Moles of silicon remained after reaction = 3.285 - 1.4475 = 1.8375 moles
To calculate the amount of Silicon left in excess is calculated by using equation 1:
Amount of Silicon in excess will be 51.45 grams.