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3 years ago

How many Joules of heat are required to melt 250 grams of ice at 0°C?

Chemistry

1 answer:

Molodets [167]3 years ago

5 0

Heat required : Q = 83500 J = 83.5 kJ

<h3> Further explanation </h3>

Given

mass ice = 250 g at 0°C

Required

The heat required

Solution

The heat to change the phase can be formulated :

Q = m.Lf (melting/freezing)

Lf=latent heat of fusion

Input the value :

Q = 250 g x 334 J/g

Q = 83500 J

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The estimated costs for remodelling the interior of an apartment are: three 1-gallon cans of paint at $15.44 each, two paint bru

Vlad1618 [11]

The total estimated cost with the appropriate significant figures is

$195,13.

Any two non-zero digits that are separated by a zero are important. For instance, the number 108.0097 has seven significant digits. Every zero that is both to the right and left of a non-zero digit and the decimal point is never meaningful. For instance, the number 0.00798 had three significant digits.

Simply multiply the required number of goods by their individual costs, then add them all up to calculate this:

3*13,69= 41,07 2*9,53=19,06 \s1*135= 135

Total cost: $41,07 plus $19,06 plus 135 equals $55,13.

Thus, the overall price will be $195,13.

Learn more about significant figures here-

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2 years ago

Iron (III) oxide and hydrogen react to form iron and water, like this: Fe 03(s)+3H9)2Fe(s)+3HO) At a certain temperature, a chem

belka [17]

The question is incomplete, here is the complete question:

Iron (III) oxide and hydrogen react to form iron and water, like this:

$Fe_2O_3(s)+3H_2(g)\rightarrow 2Fe(s)+3H_2O(g)$

At a certain temperature, a chemist finds that a 8.9 L reaction vessel containing a mixture of iron(III) oxide, hydrogen, Iron, and water at equilibrium has the following composition.

Compound Amount

Fe₂O₃ 3.95 g

H₂ 4.77 g

Fe 4.38 g

H₂O 2.00 g

Calculate the value of the equilibrium constant Kc for this reaction. Round your answer to 2 significant digits.

<u>Answer:</u> The value of equilibrium constant for given equation is $1.0\times 10^{-4}$

<u>Explanation:</u>

To calculate the molarity of solution, we use the equation:

$\text{Molarity of the solution}=\frac{\text{Mass of solute}}{\text{Molar mass of solute}\times \text{Volume of solution (in L)}}$

<u>For hydrogen gas:</u>

Given mass of hydrogen gas = 4.77 g

Molar mass of hydrogen gas = 2 g/mol

Volume of the solution = 8.9 L

Putting values in above expression, we get:

$\text{Molarity of hydrogen gas}=\frac{4.77}{2\times 8.9}\\\\\text{Molarity of hydrogen gas}=0.268M$

<u>For water:</u>

Given mass of water = 2.00 g

Molar mass of water = 18 g/mol

Volume of the solution = 8.9 L

Putting values in above expression, we get:

$\text{Molarity of water}=\frac{2.00}{18\times 8.9}\\\\\text{Molarity of water}=0.0125M$

For the given chemical equation:

$Fe_2O_3(s)+3H_2(g)\rightarrow 2Fe(s)+3H_2O(g)$

The expression of equilibrium constant for above equation follows:

$K_{eq}=\frac{[H_2O]^3}{[H_2]^3}$

Concentration of pure solids and pure liquids are taken as 1 in equilibrium constant expression.

Putting values in above expression, we get:

$K_{c}=\frac{(0.0125)^3}{(0.268)^3}\\\\K_{c}=1.0\times 10^{-4}$

Hence, the value of equilibrium constant for given equation is $1.0\times 10^{-4}$

6 0

4 years ago

If a question cannot be tested or observed it cannot be answered by science? True or false??

Triss [41]

the answers going to be false

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4 years ago

Read 2 more answers

What types of substances would definitely be good conductors?

serious [3.7K]

Answer: Ionic substances would be good conductors since they dissolve in water and form ions.

Explanation:

Conductors can be defined as those materials which can allow the electricity to flow through them. The conductors also allow the transmission of heat and light from one to another source. They conduct electricity by allowing the electrons to flow through them easily.

The ionic substances can be good conductors because these can be dissolved in water and they will produce ions. The positively-charged ions will be attracted towards the negative electrode whereas the negatively charged ions to the positive electrode.

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3 years ago

If the power source in a motor was to be replaced with an electrical load, and the armature was turned by hand, then what device

timofeeve [1]

Answer:

This question doesnt make much sense but ill try to answer it.

A brushed DC electric motor is an internally commutated electric motor designed to be run from a direct current power source. Brushed motors were the first commercially important application of electricity. If the shaft of a DC motor is turned by an external force, the motor will act as a generator. DC Motor rotation does have to do with the voltage polarity and the direction of the current flow.

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