Answer:
The volume of helium at 25.0 °C is 60.3 cm³.
Explanation:
In order to work with ideal gases we need to consider absolute temperatures (Kelvin). To convert Celsius to Kelvin we use the following expression:
K = °C + 273.15
The initial and final temperatures are:
T₁ = 25.0 + 273.15 = 298.2 K
T₂ = -196.0 + 273.15 = 77.2 K
The volume at 77.2 K is V₂ = 15.6 cm³. To calculate V₁ in isobaric conditions we can use Charle's Law.
The density does not change because it is still the same liquid as before
Answer : The rms speed of the molecules in a sample of 
gas at 300 K will be four times larger than the rms speed of 
molecules at the same temperature, and the ratio 
constant with increasing temperature.
Explanation :
Formula used for root mean square speed :
where,
= rms speed of the molecule
R = gas constant
T = temperature
M = molar mass of the gas
At constant temperature, the formula becomes,
And the formula for two gases will be,
Molar mass of = 32 g/mole
Molar mass of = 2 g/mole
Now put all the given values in the above formula, we get
Therefore, the rms speed of the molecules in a sample of gas at 300 K will be four times larger than the rms speed of molecules at the same temperature.
And the ratio constant with increasing temperature because rms speed depends only on the molar mass of the gases at same temperature.
Answer:
Option b.
The triple point of a substance is the temperature and pressure conditions at which states of a substance coexist at equilibrium
Answer:
A. Mafic; iron and/or magnesium
Explanation:
Let's find the answer by naming some minerals and their chemistry.
Mafic minerals are dark-colored whereas felsic minerals are light-colored, thats way mafic rocks are dark-colored because they are mainly composed by mafic minerals and the other way around for felsic rocks.
But remember that mafic minerals as amphiboles, pyroxenes or biotites, involve in their chemical structure iron and/or magnesium. Although calcium and sodium can be incorporated in amphiboles and clinopyroxenes, they are not involved in orthopyroxenes and biotites. On the other hand, although potassium is involved in biotite and in some extent in amphiboles, this element is not involved in pyroxenes.
So in conclusion, mafic minerals are usually dark-colored because they involve iron and/or magnesium in their chemical structures.
