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kenny6666 [7]
3 years ago
5

Describe what happens when two substances at different temperatures come into contact. Describe how the law of conservation of e

nergy applies to this system.
Chemistry
1 answer:
Mrac [35]3 years ago
3 0
When two substances at different tempeartures como into contact, the substance that is at higher temperature will transfer energy, in the form of heat, to the substance that is at lower temperature, until their temperatures get equal.

In this case, if the two substances are isolated of the rest of the universe, the law of conservation of energy states tha the heat released by the substance initially at higher temperature is the same amount of heat gained by the substance originally at lower temperature.

 
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B) SO₃(g) + H₂O(l) → H₂SO₄(aq)
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2 years ago
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5. How much heat (in calories) is absorbed by a reaction when
Wewaii [24]

Answer:

1.2 × 10⁴ cal

Explanation:

Given data

  • Mass of water (m): 300 g
  • Initial temperature: 80 °C
  • Final temperature: 40°C

We can calculate the heat released by the water (Q_w) when it cools using the following expression.

Q_w = c \times m \times (T_f - T_i)

where

c is the specific heat capacity of water (1 cal/g.°C)

Q_w = \frac{1cal}{g.\°C}  \times 300g \times (40\°C - 80\°C) = -1.2 \times 10^{4} cal

According to the law of conservation of energy, the sum of the heat released by the water (Q_w) and the heat absorbed by the reaction (Q_r) is zero.

Q_w + Q_r = 0\\Q_r = -Q_w = 1.2 \times 10^{4} cal

7 0
2 years ago
What is the percent yield of O2 if 10.2 g of O2 is produced from the decomposition of 17.0 g of H2O?
yawa3891 [41]

The balanced chemical reaction will be:

2H2O = 2H2 + O2

<span>We are given the amount of water used in the decomposition reaction. This will be our starting point.</span>

<span>17.0 g H2O</span> (1 mol  H2O/ 18.02 g H2O) (1 mol O2/2 mol <span>H2O</span>) ( 32.00 g O2/1mol O2) = 15.09 g O2

Percent yield = actual yield / theoretical yield x 100

<span>Percent yield =10.2 g / 15.09  g x 100</span>

Percent yield = 67.58%

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2 years ago
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When preparing the diazonium salt, the solution is tested with potassium iodide-starch paper. a positive test is the immediate f
Dahasolnce [82]
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8 0
3 years ago
How many grams of MgCl2 (molar mass = 95.20 g/mol) will be formed from 25.6 mL of a 0.100 M HCL solution reacting with excess ma
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The balanced equation for the above reaction is as follows;
Mg + 2HCl ---> MgCl₂ + H₂
stoichiometry of HCl to MgCl₂ is 2:1
we have been told that Mg is in excess therefore HCl is the limiting reactant 
number of HCl moles reacted - 0.100 mol/L x 0.0256 L = 0.00256 mol
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3 0
2 years ago
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