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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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Which situation is the best example of regulation in an economic system?
velikii [3]

Hope this helps!

Answer: The correct option is: "A state agency has been created to monitor the production and distribution of sports drinks."

Explanation:

The economic regulation are the provisions through which the government intervenes in the markets to set prices or quantities of production, or establish technical specifications and in general, restrictions that must be met by citizens and companies to participate in a market.

5 0
1 year ago
A student visits the beach during a very hot day. She steps on the sand and jumps because it is so hot. What type of heat transf
sammy [17]
Answer is: thermal conductuction.
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3 0
3 years ago
Read 2 more answers
How would you make a 2.00L of 0. 500M sodium chloride solution. (assume you have a fully equipped lab with water); sketch, calc
Gwar [14]

Answer:

Sodium chloride solution:

First you need to calculate the mass of salt needed (done in the explanation), which is 58.44g. Then it have to be weighted in an analytical balance in a weighting boat and then transferred into a 2L volumetric flask that is going to be filled until the mark with distilled water.

Sulfuric acid dilution:

First you need to calculate the volume needed (done in the explanation), it is 16.6 mL. Using a graduated pipette one measures this volume and transfer it into a 2L volumetric flask that is already half filled with distilled water, and then one fills it until its mark.

Explanation:

Sodium chloride solution:

Each liter of a 0.500M solution has half mol, so 2L of said solution has 1 mol of salt. Sodium chloride molar mass is 58.44g/mol, so in 2L of solution there is 58.44g of salt. That`s the mass that`s going to be weighted and transferred to a 2L volumetric flask.

Sulfuric acid dilution:

This is the equation for dilution of solutions:

c_{1} v_{1} =c_{2} v_{2}

Where "c1" stands for the initial concentration (stock solution concentration), "v1" for the initial volume (volume of stock solution used), "c2" for the desired concentration and "v2" for the desired volume.

When we are diluting from a stock solution we want to know how much do we have to pipette from the stock solution into our volumetric flask. We do so by isolating the "v1" term from the dilution equation:

v_{1} =\frac{c_{2} v_{2} }{c_{1} }

in this case that would be:

v_{1} =\frac{0.100 x2.0 }{12.0 }=0.0166L=16.6mL

5 0
3 years ago
What's the atomic weight of salt ?
marta [7]

Answer:

58.44 g/mol

Explanation:

58.44 g/mol

4 0
2 years ago
Read 2 more answers
Pyridine, C5H5N, is a polar organic solvent. How many carbon atoms are in 7.05 moles of pyridine? 4.24 x 1024 4.24 x 10, 24 2.12
leonid [27]

Answer:

2.122×10^25atoms

Explanation:

number of moles=mass/molar mass

7.05moles= mass of pyridine/79

reacting mass of pyridine=556.95

C5H5N= (12×5)+(5)+(14)=79

C5=60

to find the mass of carbon in 556.95g of pyridine we take the stoichometric ratio

60[C5] -----> 79[C5H5N]

x[C5] --------> 556.95g[C5H5N]

cross multiply

x=(60×556.95)/79

x=423g of carbon

moles=mass/molar mass

moles of carbon=423/12

moles=35.25moles of carbon

moles=number of particles/Avogadro's constant

35.25=number of particles/6.02×10^23

number of particles=2.122×10^25atoms of carbon

3 0
2 years ago
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