A cup of coffee(140g) cools from 75 degrees Celsius down to comfortable room temperature 20 degrees Celsius. How much energy doe
1 answer:
Energy releases to the surroundings = -32.2 kJ
<h3>Further explanation </h3>Heat can be calculated using the formula:
Q = mc∆T
Q = heat, J
m = mass, g
c = specific heat, joules / g ° C
∆T = temperature difference, ° C / K
mass of coffee(m) = 140 g
∆T = temperature difference :
final temperature - initial temperature = 20-75=-55°C
specific heat coffee= specific heat water = 4.18 J/g° C
The heat releases :
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Answer:
Net charge in serine at pH equal to 8.30 is "0"
Explanation:
- At pH >
, carboxyl group exists as
(charged)
- At pH <
- At pH >
(neutral)
- At pH <
(charged)
- So, at pH = 8.30, both carboxyl and amino group exists in charged state.
- Net charge in serine at pH equal to 8.30 is "0".
- Structure of serine at pH equal to 8.30 has been shown below.
The mass of water (H₂O) that would be produced is 4.5 g
<h3>Stoichiometry </h3>From the question, we are to determine the mass of water that would be produced.
From the given balanced chemical equation
2C₂H₆ +7O₂ → 4CO₂ +6H₂O
This means
2 moles of C₂H₆ reacts with 7 moles of O₂ to produce 4 moles of CO₂ and 6 moles of H₂O
Now, we will determine the number of moles of each reactant present
- For Ethane (C₂H₆)
Mass = 2.5 g
Molar mass = 30.07 g
Using the formula,
Number of moles of C₂H₆ present =
Number of moles of C₂H₆ present = 0.08314 mole
- For Oxygen (O₂)
Mass = 170g
Molar mass = 31.999 g/mol
Number of moles of O₂ present =
Number of moles of O₂ present = 5.3127 moles
Since
2 moles of C₂H₆ reacts with 7 moles of O₂
Then,
0.08314 mole of C₂H₆ will react with
= 0.58198 mole
Therefore,
0.08314 mole of C₂H₆ reacts with 0.58198 mole of O₂ to produce 3 × 0.08314 moles of H₂O
3 × 0.08314 = 0.24942 mole
Thus, the number of moles of water (H₂O) produced is 0.24942 mole
Now, for the mass of water that would be produced,
Using the formula,
Mass = Number of moles × Molar mass
Molar mass of water = 18.015 g/mol
Then,
Mass of water that would be produced = 0.24942 × 18.015
Mass of water that would be produced = 4.4933 g
Mass of water that would be produced ≅ 4.5 g
Hence, the mass of water (H₂O) that would be produced is 4.5 g
Learn more on Stoichiometry here: brainly.com/question/14271082