The children’s playful acts made their parents roar with laughter

Ice cream is made by freezing a liquid mixture that, as a first approximation, can be considered a solution of sucrose in water.

hjlf

Answer:

Freezing point is -2.81°C

Explanation:

34g/342gmol^-1 = 0.0994mol

n = m/mr

Molarity= 0.994/ 0.66 = 1.51M

◇T = -i × m ×Kf

Where ◇T is freezing depression

i= Vant Hoff factor

m = molarity

Kf = freezing content = 1.

860kgmol^-1

◇T =-1 × 1.51 × 1.860 = - 2.81°C

6 0

3 years ago

Carson’s class visited a hydroelectric plant on a field trip during their study of energy. The process interested him, and he ha

AURORKA [14]

Answer:

look in your science book

Explanation:

7 0

2 years ago

All of the following are possible sources of error in a scientific investigation except for

Dimas [21]

Answer: Common sources of error include instrumental, environmental, procedural, and human. All of these errors can be either random or systematic depending on how they affect the results. Make sure you have your problem, hypothesis, evidence, analyze the data, ask yourself if the evidence supports ur hypothesis, draw conclusions, and communicate your results!

Explanation:

6 0

3 years ago

Read 2 more answers

When a 12.8 g sample of KCL dissolves in 75.0 g of water in a calorimeter the temp. drops from 31 Celsius to 21.6 Celsius. Calcu

Delicious77 [7]

Answer:

Step 1: Calculate qsur (the surrounding is

usually the water)

qsur = ? J

m = 75.0 g water

c = 4.184 J/g

oC

ΔT = (Tfinal- Tinitial)= (21.6 – 31.0) = -9.4 oC

qsur = m · c · (ΔT)

qsur = (75.0g) (4.184 J/g

oC) (-9.4 oC)

qsur = - 2949.72 J

First, using the information we know that we

must solve for qsur, which is the water. We know

the mass for water, 75.0g, the specific heat of

the water, 4.184 j/g

o

c, and the change in

temperature, 21.6-31.0 = -9.4 oC. Plugging it

into the equation, we solve for qsur.

Step 2: Calculate qsys qsys = - (qsur)

qsys = - (- 2949.72 J)

qsys = + 2949.72

In this case, the qsur is negative, which means

that the water lost energy. Where did it go? It

went to the system. Thus, the energy of the

system is negative, opposite, the energy of the

surrounding.

Step 3: Calculate moles of the substance

that is the system

Given: 12.8 g KCl

Mol system = (g system given)

(molar mass of system)

Mol system = (12.8 g KCl)

(39.10g + 35.45g)

Mol system = 12.8 g KCl

74.55 g

Mol system = 0.172

Here, we solve for the mol in the system by

using the molar mass of the material in the

system.

Step 4: Calculate ΔH ΔH = q sys .

Mol system

ΔH= + 2949.72 J

0.172 mol

ΔH= +17179.81 J/mol or +1.72 x 104

J/mol

i hope this helps

7 0

3 years ago

1. A sample of oxygen is collected over water at 22 ° C and 762 torr. What is the partial pressure of the dry oxygen? The vapor

Rom4ik [11]

Answer: The partial pressure of the dry oxygen is 742 torr

Explanation:

Dalton's Law of Partial Pressure states that the total pressure exerted by a mixture of gases is the sum of partial pressure of each individual gas present. Thus $P(total)=P_1+P_2 .........$

Given; Total pressure = 762 torr

partial pressure of water = 19.8 torr

partial pressure of dry oxygen = ? torr

Total pressure = partial pressure of water + partial pressure of dry oxygen

762 torr = 19.8 torr = partial pressure of dry oxygen

partial pressure of dry oxygen = 742 torr

The partial pressure of the dry oxygen is 742 torr

8 0

3 years ago