Answer:
B. a piece of paper being torn
Explanation:
A chemical change is one that cannot be reversed. This means the original properties of the substance or object cannot be restored.
If you cook a raw egg, it would turn into a boiled egg (or a poached egg, however it is being cooked). The reaction is irreversible, so you cannot turn the cooked egg back into a raw egg - it is basically impossible to 'uncook' an already cooked egg.
When you toast a piece of bread, it turns into toast. You can't 'untoast' it back into bread. The chemical changes have already occurred and cannot be undone.
If you tear a piece of paper, it is still paper. You are only ripping it, not changing anything about it. You could simply tape the torn bit back to the original bit, or glue it - either way, it is still paper and nothing has occurred to drastically change the physical state of it.
Therefore, B is not a chemical change.
Answer:
The answer is ""
Explanation:
For point a:
Energy balance equation:
From the above equation:
because the rate of air entering the tank that is constant.
Since the tank was initially empty and the inlet is constant hence,
Interpolate the enthalpy between . The surrounding air
temperature:
Substituting the value from ideal gas:
Follow the ideal gas table.
The and between temperature
Interpolate
Substitute values from the table.
For point b:
Consider the ideal gas equation. therefore, p is pressure, V is the volume, m is mass of gas. (M is the molar mass of the gas that is and R is gas constant), and T is the temperature.
For point c:
Entropy is given by the following formula:
<span>Cells undergo mitosis for three main reasons:
-To repair and/or replace old or damaged cells.
-During periods of cell and tissue growth
-When the body needs exact replicas/copies of cells e.g. hair cells and blood cells.</span>
The work done on the sail is 600 J
Explanation:
The work done to lift the sail is equal to the gain in gravitational potential energy of the sail, therefore is:
where
m is the mass of the sail
g is the acceleration of gravity
(mg) is the weight of the sail
is the change in height of the sail
In this problem we have
mg = 150 N (weight)
Substituting, we find the work done:
Learn more about work:
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Answer:
28.6 ohm
Explanation:
there is a 3rd resistor in series. voltage drop across the resistors will be equal to 60v
7*.2+7*.2 +.2x = 60
2.8+.2x = 60
.2x = 57.2
x = 28.6