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atroni [7]
3 years ago
8

What is the total amount of heat released when 94.0 g water at 80.0 °C cools to form ice at −30.0 °C?

Chemistry
1 answer:
Wewaii [24]3 years ago
6 0

Answer:

The total amount of heat released  is  68.7 kJ

Explanation:

Given that:

mass of water = 94.0 g

moles of water = 94 / 18.02 = 5.216

80⁰C   ------>  0⁰C  -------->    -30⁰C

Q1 = m Cp dT

      = 94 x 4.184 x (0 - 80)

     = -31463.68 J

     = -31.43 kJ

Q2 = 6.01 x 10^3 x 5.216

    = - 31348.16 J

   = -31.35 kJ

Q3 = - 94 x 2.09 x 30

    = - 5893.8 J

   = -5.894 kJ

Total heat = Q1 + Q2 + Q3  = -31.43 kJ  + (-31.35 kJ  ) + (-5.894 kJ )  = -68.7 kJ

Total heat released = -68.7 kJ

Note that the "negative sign" simply indicates heat released, therefore no need to put it in the answer.

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What eventually happens to gas if its pressureis increased?​
balu736 [363]

Answer:

the rate increases

Explanation:

they are closer to each other, they will collide with each other more frequently and more successful collision

4 0
3 years ago
If 0.138g of cyclohexene (c6h10) was obtained from 0.240g of cyclohexanol (c6h120), what is the percentage yield of cyclohexene?
tino4ka555 [31]
<span>Given in the question- 1 mole of cyclohexanol = > 1 mole of cyclohexene Molar mass 100.16 g/mol moles of cyclohexanol = .240 / 100.16= 0.002396 moles Molar mass 82.143 g/mol moles of cyclohexene formed @100 % yield = 0.002396 Molar mass 82.143 g/mol mass of cyclohexene @ 100 % = .002396 x 82.143 = 0.197g bur we have .138g so % yield = .138 / .197 = 70.0 % Ans- 70 percentage yield of cyclohexene.</span>
4 0
3 years ago
A 2.026g sample of a hydrate of sodium carbonate (Na2CO3) is heated to remove water. After heating, the mass of the sample is 0.
OLEGan [10]

Answer:

62.98 % of the sample of hydrate is water

Explanation:

Step 1: Data given

Mass of the sample of a hydrate of sodium carbonate (Na2CO3) = 2.026 grams

After heating, the mass of the sample is 0.750 g

Molar mass H2O = 18.02 g/mol

Step 2: Calculate mass of water

Mass water = mass of hydrate - mass of sample after heating

Mass water = 2.026 grams - 0.750 grams

Mass water = 1.276 grams

Step 3: Calculate mass % percent of water

Mass % of water = (mass of water / total mass hydrate) * 100 %

Mass % of water = (1.276 grams / 2.026 grams) *100 %

Mass % of water = 62.98 %

62.98 % of the sample of hydrate is water

7 0
3 years ago
Read 2 more answers
How much energy must a 10 gram block of ice gain in order to melt ?
Minchanka [31]

Answer:

the answer is 10 times

Explanation:

because it takes 10 times as much energy -3330 j - to melt 10.0 grams of ice.

8 0
2 years ago
How fast is an electron travelling If it has a wavelength of 8.20 km?
Lemur [1.5K]

The electron is travelling with a velocity of 1.123 × 10⁷m/s if it has a wavelength of 8.20 km.

<h3>How to calculate velocity of an electron?</h3>

The velocity at which an electron travels can be calculated using the following formula:

λ = h/mv

Where;

  • H = Planck's constant
  • m = mass of electron
  • v = velocity of electron
  • λ = wavelength

  • Planck's constant (h) = 6.626 × 10−³⁴ J⋅s.
  • mass of electron (m) = 9.109 × 10−³¹ kg
  • wavelength = 8200m

8200 = 6.626×10−³⁴ / 9.109 × 10−³¹V

8200 = 7.3 × 10-⁴V

V = 8200 ÷ 7.3 × 10-⁴

V = 1.123 × 10⁷m/s

Therefore, the electron is travelling with a velocity of 1.123 × 10⁷m/s if it has a wavelength of 8.20 km.

Learn more about velocity at: brainly.com/question/13171879

#SPJ1

5 0
1 year ago
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