WHY ARE FROGS SAID to have "two lives?'
2 answers:
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Answer:
The heat absorbed by the sample of water is 3,294.9 J
Explanation:
Calorimetry is the measurement and calculation of the amounts of heat exchanged by a body or a system.
The sensible heat of a body is the amount of heat received or transferred by a body when it undergoes a temperature variation (Δt) without there being a change of physical state (solid, liquid or gaseous). Its mathematical expression is:
Q = c * m * ΔT
Where Q is the heat exchanged by a body of mass m, made up of a specific heat substance c and where ΔT is the temperature variation.
In this case:
- Q=?
- m= 45 g
- c= 4.184
- ΔT= Tfinal - Tinitial= 38.5 C - 21 C= 17.5 C
Replacing:
Q= 4.184 * 45 g* 17.5 C
Solving:
Q=3,294.9 J
<u><em>The heat absorbed by the sample of water is 3,294.9 J</em></u>
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The question is incomplete, here is the complete question:
Urea (CH₄N₂O) is a common fertilizer that can be synthesized by the reaction of ammonia (NH₃) with carbon dioxide as follows: 2NH₃(aq) + CO₂(aq) → CH₄N₂O(aq) + H₂O(l) In an industrial synthesis of urea, a chemist combines 135.9 kg of ammonia with 211.4 kg of carbon dioxide and obtains 178.0 kg of urea.
Determine the limiting reactant. (express your answer as a chemical formula)
<u>Answer:</u> The limiting reactant is ammonia
<u>Explanation:</u>
To calculate the number of moles, we use the equation:
.....(1)
- <u>For ammonia:</u>
Given mass of ammonia = 135.9 kg = 135900 g (Conversion factor: 1 kg = 1000 g)
Molar mass of ammonia = 17 g/mol
Putting values in equation 1, we get:
- <u>For carbon dioxide gas:</u>
Given mass of carbon dioxide gas = 211.4 kg = 211400 g
Molar mass of carbon dioxide gas = 44 g/mol
Putting values in equation 1, we get:
The given chemical reaction follows:
By Stoichiometry of the reaction:
2 moles of ammonia reacts with 1 mole of carbon dioxide
So, 7994.12 moles of ammonia will react with = of carbon dioxide
As, given amount of carbon dioxide is more than the required amount. So, it is considered as an excess reagent.
Thus, ammonia is considered as a limiting reagent because it limits the formation of product.
Hence, the limiting reactant is ammonia