Answer:
232.5 g C2H6O2
Explanation:
The equation you need to use here is ΔTf = i Kf m
Since pure water freezes at 0 C, your ΔTf is just 4.46 C
i = 1 (ethylene glycol is a weak electrolyte)
Kf = molal freezing constant, which for water is 1.86 C/m
m = molality = x mols C2H6O2 / 1.15 kg H2O (don't know the moles of ethylene glycol we're dissolving yet)
Than,
4.46 C = 1.86 C/m (x mol C2H6O2 / 1.15 kg H2O)
Solve for x, you should get x = 2.75 mol C2H6O2
3.75 mol C2H6O2 (62 g C2H6O2 / 1 mol C2H6O2) = 232.5 g C2H6O2
Answer:
B. They don't understand how red shift affects stars.
Explanation:
Astronomers face difficulty in observing distant stars because they are so far that they are easily viewed by telescope. Light pollution is major concern in present times . There is very less window present for observation. The dim light from the distance stars also gets distorted due to atmosphere and effects astronomical seeing.
Astronomers are aware about the Doppler effect for light that is the redshift effect on the star light. It is not a difficulty for astronomers.
<span>Yes, the material will float because it has a lower density than that of water.
A material will float if it has a lower density than that of the liquid it's placed in. So let's first calculate the density of this new material.
Density is simply mass per volume, so doing the division.
2.0 g / 3.0 cm^3 = 0.67 g/cm^3
The density of water is 1.0 g/cm^3 and since the density of the new material is less at 0.67 g/cm^3 it will float.</span>
Answer:
None of the above.
Explanation:
The limiting factor of this is the chlorine. You only have 2 moles of chlorine.
2Na + Cl_2 ==> 2*NaCl
The equation tells you that for every mol of Cl2 that you have, you require 2 moles of Na and you get 2 moles of NaCl
So what that means is that if you have 2 mols of Cl2, you need just 4 moles of Na, and you will get 4 mols of NaCl
Since 4 is not one of your choices, the answer is none of the above
