Which cohesive forces are the strongest in water?

the specific heat capacity of water is 1 cal/gc how much heat in calories is released when 25.7 of water is cooled from 85 to 49

liraira [26]

Answer:

The amount of heat that is released is -925.2 cal

Explanation:

Calorimetry is the measurement and calculation of the amounts of heat exchanged by a body or a system.

Sensible heat is the amount of heat that a body can receive or release without affecting its molecular structure, that is, it does not change the state (solid, liquid, gaseous). In other words, sensible heat is the amount of heat that a body absorbs or releases without any changes in its physical state.

The equation that allows to calculate heat exchanges is:

Q = c * m * ΔT

Where Q is the heat exchanged by a body of mass m, constituted by a substance of specific heat c and where ΔT is the variation in temperature.

In this case:

c= 1 $\frac{cal}{g*C}$
m= 25.7 g
ΔT= Tfinal - Tinitial= 49 °C - 85 °C= -36 °C

Replacing:

Q= 1 $\frac{cal}{g*C}$ *25.7 g* (-36 C)

Solving:

Q= -925.2 cal

<u><em>The amount of heat that is released is -925.2 cal</em></u>

8 0

3 years ago

You weighed out 0.020 g of your crude aspirin product in order to determine the amount of salicylic acid impurity. Following the

Kitty [74]

Answer:

The correct answer is 7.8 percent.

Explanation:

As mentioned in the given question, the absorbance (A) of the sample solution is 1.07. To find the concentration of aspirin, Beer's law is used, that is, A = ebc

Here, e is the extinction coefficient, which is equal to 139.322 M^-1cm^-1 as per the standard value for salicylic acid, b is the pathlength, which is equivalent to 1 cm. Now putting the values we get,

A = ebc

c = A / (eb)

c = 1.07 / (139.322 × 1)

c = 0.00768 M

Now to determine the percent salicylic acid in the sample, there is a need to compare the value of concentration determined with the concentration of aspirin given initially.

0.02 grams is the initial concentration of aspirin mentioned in the question. The molar mass of aspirin is 240 g/mol.

Therefore, the moles of aspirin will be,

0.02 / 240 = 8.33 × 10^-5 moles

The final volume of the diluted solution given is 10 ml or 0.01 liters.

The molarity of aspirin in the diluted solution will be,

c1 = 8.33 × 10^-5 / 0.01 = 8.33 × 10^-3 M or 0.00833 M

Now, the percent of salicylic acid in the product will be,

c1 - c / c1 × 100

(0.00833 - 0.00768) / 0.00833 × 100 = 7.8 %

5 0

3 years ago

During an experiment, ice and water were placed in a perfectly insulated thermos flask at 0 °C. Describe this system when it pha

Ivanshal [37]

Answer :By the time thermal equilibrium is attained in the system, ice is completely converted to water.

What is tehrmal equilibrium?

Thermal equilibrium is a situation in which two substances are exactly at the same temperature. That is. Heat is no longer flowing beween the bodies.

Recall that an insulated thermos flask implies that heat does not eneter or leave the system. Heat will flow from the water to the ice untill the both attains the same temperature and the ice is completely converted to water.

Have a good day

5 0

2 years ago

Use the following equation to answer the questions and please show all work.

DIA [1.3K]

Answer:

a.36 g of water is produced.

b.64 g of $O_{2}$ is consumed.