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2 years ago

A statement of the first law of thermodynamics is that:

Chemistry

1 answer:

Vladimir79 [104]2 years ago

4 0

Answer: Option A) the total energy of the universe is constant.

Explanation:

The first law of thermodynamics is also known as the law of conservation of mass.

And it states that matter is neither created nor destroyed during a chemical reaction but changes from one form to another.

Thus, the total energy of the universe is constant (neither created nor destroyed).

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A person is pushing a box across a table. The measured forces on the box are 10N, 14N, 7N, 10N. Which force is represented by 7N

Vlad1618 [11]

Answer: The friction force.

Justification:

Since the box is sliding over the table, the normal force equals the weight of the object (and any other vertical force that is applied on the box).

So, the normal force and weight (along with any other vertical component of a force applied on the box) must be 10 N and 10 N.

The other two forces: 14 N and 7 N are the forces in the plane of the table and should be opposite in a same line. The 14 N force is the responsible of the motion and the 7N force is opposing the 14 N force, so the 7N force has to be the friction force. Of course, 14N - 7N > 0 which is why the box is moving.

3 0

2 years ago

Read 2 more answers

Look at the reaction below and state which direction the reaction would shift:

lorasvet [3.4K]

Answer:

there is no change at all!!!

4 0

2 years ago

What is the composition, in atom percent, of an alloy that consists of a) 5.5 wt% Pb and b) 94.5 wt% of Sn? Assume that the atom

Anastaziya [24]

Answer : The percent composition of Pb and Sn in atom is, 3.21 % and 96.8 % respectively.

Explanation :

First we have to calculate the number of atoms in 5.5 wt% Pb and 94.5 wt% of Sn.

As, 207.2 g of lead contains $6.022\times 10^{23}$ atoms

So, 5.5 g of lead contains $\frac{5.5}{207.2}\times 6.022\times 10^{23}=1.59\times 10^{22}$ atoms

and,

As, 118.71 g of lead contains $6.022\times 10^{23}$ atoms

So, 94.5 g of lead contains $\frac{94.5}{118.71}\times 6.022\times 10^{23}=4.79\times 10^{23}$ atoms

Now we have to calculate the percent composition of Pb and Sn in atom.

$\% \text{Composition of Pb}=\frac{\text{Atoms of Pb}}{\text{Atoms of Pb}+\text{Atoms of Sn}}\times 100$

$\% \text{Composition of Pb}=\frac{1.59\times 10^{22}}{(1.59\times 10^{22})+(4.79\times 10^{23})}\times 100=3.21\%$

and,

$\% \text{Composition of Sn}=\frac{\text{Atoms of Sn}}{\text{Atoms of Pb}+\text{Atoms of Sn}}\times 100$

$\% \text{Composition of Sn}=\frac{4.79\times 10^{23}}{(1.59\times 10^{22})+(4.79\times 10^{23})}\times 100=96.8\%$

Thus, the percent composition of Pb and Sn in atom is, 3.21 % and 96.8 % respectively.

6 0

2 years ago

5. To keep your lunch cold at the beach, would you want a material

Leya [2.2K]

Answer:

Minimizes heat transfer

Explanation:

To keep my lunch from getting cold at the beach, a material the minimizes heat transfer will be the most desirable.

Such material should be modified to prevent had transfer by convection, conduction and radiation.
This kind of material is desirable because heat generally flows from a place of high amount to that of low amount.
Since the food will mostly have a temperature higher than the ambient one, it is expected that heat will flow away from the food to the environment.
This will make the food cold.
If such heat transfer is prevented, then, the food will remain hot.

4 0

2 years ago

4. How does the kinetic theory of gases explain the weather changes happening in the troposphere? You can also research on the I

uranmaximum [27]

According to the kmt pressure is directly proportional to the number of collision between particles

4 0

2 years ago

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