Ask question

Ask question

All categories

2 years ago

5

In an area in which electricity costs 8 cents/kilowatt-hour, a 5 kW clothes dryer runs for 90 minutes to dry a load of laundry.

How much did it cost to dry these clothes?

1 answer:

Orlov [11]2 years ago

4 0

90 minutes is 1.5 hours.

5 kW * 1.5 hours = 7.5 kWh

8c/kWh * 7.5 kWh = 60 cents

You might be interested in

What is the resistance of a 150 W lightbulb connected to a 24 V voltage source?

Luda [366]

Answer:

3.84 Ω

Explanation:

From the question given above, the following data were obtained:

Electrical power (P) = 150 W

Voltage (V) = 24 V

Resistance (R) =?

P = IV

Recall:

V = IR

Divide both side by R

I = V/R

P = V/R × V

P = V² / R

Where:

P => Electrical power

V => Voltage

I => Current

R => Resistance

With the above formula (i.e P = V²/R), we can calculate resistance as illustrated below:

Electrical power (P) = 150 W

Voltage (V) = 24 V

Resistance (R) =?

P = V²/R

150 = 24² / R

150 = 576 / R

Cross multiply

150 × R = 576

Divide both side by 150

R = 576 / 150

R = 3.84 Ω

Thus, the resistance is 3.84 Ω

4 0

2 years ago

9. Which of the following is true?

wlad13 [49]

The answer should be C

6 0

3 years ago

Zinc sulfate is a 2-ion electrolyte,

Gekata [30.6K]

<u>Answer:</u> The value of <em>i</em> is 1.4 and 40% dissociation of 100 particles of zinc sulfate will yield 60 undissociated particles.

<u>Explanation:</u>

The equation used to calculate the Vant' Hoff factor in dissociation follows:

$\alpha =\frac{i-1}{n-1}$

where,

$\alpha$ = degree of dissociation = 40% = 0.40

i = Vant' Hoff factor

n = number of ions dissociated = 2

Putting values in above equation, we get:

$0.40=\frac{i-1}{2-1}\\\\0.40=i-1\\\\i=1.4$

The equation used to calculate the degee of dissociation follows:

$\alpha =\frac{\text{Number of particles dissociated}}{\text{Total number of particles taken}}$

Total number of particles taken = 100

Degree of dissociation = 40% = 0.40

Putting values in above equation, we get:

$0.40=\frac{\text{Number of particles dissociated}}{100}\\\\\text{Number of particles dissociated}=(0.40\times 100)=40$

This means that 40 particles are dissociated and 60 particles remain undissociated in the solution.

Hence, 40% dissociation of 100 particles of zinc sulfate will yield 60 undissociated particles.

7 0

2 years ago

is the process through which offspring are produced. A. Heredity B. Reproduction C. Conservation D. Vaccination

Dominik [7]

It is called Reproduction

6 0

3 years ago

Read 2 more answers

Using the following equation 5KNO2+2KMnO4+3H2SO4=5KNO3+2MnSO4+K2SO4+3H20. Starting with 2.47 grams of KNO2 and excess KMnO4 how

Aleonysh [2.5K]

Given equation : $5KNO_{2} + 2KMnO_{4} + 3H_{2}SO_{4}\rightarrow 5KNO_{3} + 2MnSO_{4} + K_{2}SO_{4} + 3H_{2}O$

Given information = 2.47 grams KNO2 and excess KMnO4 and we need to find grams of water (H2O).

Since KMnO4 is in excess, so grams of water(H2O) can be calculated using grams of KNO2 with the help of stoichiometry.

To find grams of water(H2O) from grams of KNO2 , we need to follow three steps.

Step 1. Convert 2.47 grams of KNO2 to moles of KNO2.

$Moles = \frac{grams}{molar mass}$

Molar mass of KNO2 = 85.10 g/mol

$Moles = 2.47 gram KNO2\times \frac{1 mol KNO2}{85.10 gram KNO2}$

Moles = 0.0290 mol KNO2

Step 2. Convert moles of KNO2 to moles of H2O using mole ratio.

Mole ratio are the coefficient present in front of the compound in the balanced equation.

Mole ratio of KNO2 : H2O is 5 : 3 (5 coefficient of KNO2 and 3 coefficient of H2O)

$0.0290 mol KNO2\times \frac{3 mol H2O}{5 mol KNO2}$

Mole = 0.0174 mol H2O

Step 3. Convert mole of H2O to grams of H2O

Grams = Moles X molar mass

Molar mass of H2O = 18.00 g/mol

$Grams = 0.0174 mol H2O\times \frac{18 g H2O}{1 mol H2O}$

Grams of water = 0.313 grams H2O

Summary : The above three steps can also be done in a singe setup as shown below.

$2.47 gram KNO2\times \frac{(1 mol KNO2)}{(85.10 gram KNO2)}\times \frac{(3 mol H2O)}{(5 mol KNO2)}\times \frac{(18.00 gram H2O)}{(1mol H2O)}$

In the above setup similar units get cancelled out and we will get grams of H2O as 0.313 grams water (H2O)

8 0

3 years ago