Answer: The original temperature was
Explanation:
Let's put the information in mathematical form:
If we consider the helium as an ideal gas, we can use the Ideal Gas Law:
were <em>R</em> is the gas constant. And <em>n</em> is the number of moles (which we don't know yet)
From this, taking 
, we have:
⇒
Now:
⇒
Answer:
29.4855 grams of chlorophyll
Explanation:
From Raoult's law
Mole fraction of solvent = vapor pressure of solution ÷ vapor pressure of solvent = 457.45 mmHg ÷ 463.57 mmHg = 0.987
Mass of solvent (diethyl ether) = 187.4 g
MW of diethyl ether (C2H5OC2H5) = 74 g/mol
Number of moles of solvent = mass/MW = 187.4/74 = 2.532 mol
Let the moles of solute (chlorophyll) be y
Total moles of solution = moles of solute + moles of solvent = (y + 2.532) mol
Mole fraction of solvent = moles of solvent/total moles of solution
0.987 = 2.532/(y + 2.532)
y + 2.532 = 2.532/0.987
y + 2.532 = 2.565
y = 2.565 - 2.532 = 0.033
Moles of solute (chlorophyll) = 0.033 mol
Mass of chlorophyll = moles of chlorophyll × MW = 0.033 × 893.5 = 29.4855 grams
The words "... as shown ..." tell us that there's a picture that goes along
with this question, and you decided not to share it. That's sad and
disappointing, but I think the question can be answered without seeing
the picture.
The net force on the crate is zero. Evidence for this is that fact that
the crate is just sitting there. If the net force on an object is not zero,
then the object is accelerating ... it's either speeding up, slowing down,
or its the direction of its motion is changing. If none of these things is
happening, then the net force on the object must be zero.
Answer: Cross-cutting features are always younger than the surrounding rock.
When material erodes before sediment is deposited on it, a geologic gap results.
Explanation:
The options include:
1. An unconformity is created when lava pours out on Earth’s surface.
2. Faults are the result of volcanic activity.
3. Intrusions and extrusions are sedimentary formations.
4. Cross-cutting features are always younger than the surrounding rock.
5. When material erodes before sediment is deposited on it, a geologic gap results.
The law of superposition simply states that when there is a layers of rocks, we would see that the younger layers will lie and be on top of the layers that are older.
Other tools that can help scientist with relative dating are:
• Cross-cutting features are always younger than the surrounding rock.
• When material erodes before sediment is deposited on it, a geologic gap results.
Answer:
3099 J
Explanation:
The increase in thermal energy corresponds to the mechanical energy lost in the process.
The mechanical energy is given by the sum of gravitational potential energy and kinetic energy of the fireman:
At the top of the pole, the fireman has no kinetic energy, so all his mechanical energy is just potential energy:
When the fireman reaches the bottom, he has no gravitational potential energy, so his mechanical energy is just given by his kinetic energy:
So, the loss in mechanical energy was
and this corresponds to the increase in thermal energy.
