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3 years ago

SCIENCEEEE!!!!! HELPPPP!!!!

Chemistry

2 answers:

Wittaler [7]3 years ago

7 0

Answer:

I would say Both are only physical changes.

Explanation:

Melting wax isn't creating a new substance, or changing the atomic structure. The wax is only changes from a solid to a liquid state. Sanding a piece if wood is usually done with sandpaper, which can physically be done with your hands. Hope this helped :)

IRINA_888 [86]3 years ago

5 0

pretty sure it's both are physical changes.

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At 373.15K and 1 atm, the molar volume of liquid water and steamare 1.88 X 10-5 m3 and 3.06 X 10-2m3, respectively. Given that t

professor190 [17]

Answer The value of $\Delta H$ and $\Delta U$ is, 40.79 kJ and 37.7 kJ respectively.

Explanation :

Heat released at constant pressure is known as enthalpy.

The formula used for change in enthalpy of the gas is:

$\Delta Q_p=\Delta H=40.79kJ/mol$

Now we have to calculate the work done.

Formula used :

$w=-P\Delta V\\\\w=-P\times (V_2-V_1)$

where,

w = work done = ?

P = external pressure of the gas = 1 atm

$V_1$ = initial volume = $1.88\times 10^{-5}m^3=1.88\times 10^{-5}\times 10^3L=1.88\times 10^{-2}L$

$V_2$ = final volume = $3.06\times 10^{-2}m^3=3.06\times 10^{-2}\times 10^3L=3.06\times 10^{1}L$

Now put all the given values in the above formula, we get:

$w=-(1atm)\times (3.06\times 10^{1}-1.88\times 10^{-2})L$

$w=-30.5812L.atm=-30.5812\times 101.3J=-3097.87556J=-3.09\times 10^3J=-3.09kJ$

Now we have to calculate the change in internal energy.

$\Delta U=q+w$

$\Delta U=40.79kJ+(3.09kJ)$

$\Delta U=37.7kJ$

Thus, the value of $\Delta H$ and $\Delta U$ is, 40.79 kJ and 37.7 kJ respectively.

4 0

3 years ago

Which of the following describes the principle of conservation of change

KiRa [710]

I think it’s c I’m not 100% sure though

5 0

2 years ago

the hcp ordered 0.2 mg of methylergonovine, and the vial contains 0.8 mg/ml. how many ml of methylergonovine should the nurse dr

olasank [31]

The volume (in mL) of methylergonovine the nurse should draw up in the syringeis is 0.25 mL

<h3>What is density? </h3>

The density of a substance is simply defined as the mass of the subtance per unit volume of the substance. Mathematically, it can be expressed as

Density = mass / volume

With the concept of density, we can obtain the volume of methylergonovine. Details below

<h3>How to determine the volume </h3>

The following data were obtained from the question:

Mass of methylergonovine = 0.2 mg
Density of methylergonovine = 0.8 mg/mL
Volume of methylergonovine =?

Density = mass / volume

Cross multiply

Density × volume = mass

Divide both sides by density

Volume = mass / density

Volume = 0.2 / 0.8

Volume of methylergonovine = 0.25 mL

Learn more about density:

brainly.com/question/952755

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8 0

1 year ago

When people conserve electricity, power plants do not need to produce as much electricity because there is less demand for it.

almond37 [142]

True

Explanation:

When people conserve electricity, power plants do not need to produce as much electricity because there is less demand for it.

This very correct.

When electricity is used in a sustainable way, there is little of it consumed.
Switching off idle electronics would make that amount of electric current to be re-distributed to another place.
Less coal and fuel would be used and power plants do not need to produce as much electricity.
Most electricity produced in power plants are often wasted due to idle appliances consuming the bulk of them.
When these appliances are turned off, less energy is in demand and less will be produced.

learn more:

Conservation of resources brainly.com/question/8690489

#learnwithBrainly

5 0

3 years ago

What are the safety procedures for nuclear accidents nowadays?

Zigmanuir [339]

Explanation:

Take shelter in a hard wall building

Close doors and windows cut off ventilation

4 0

3 years ago