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.
Answer:
23.2 mols
Explanation:
(23.2 mol H2)(2 mol H2O) /(2 mol H2) = 23.2 mol H2O
you have to do stoichiometry - so start of with what you are given, which is 23.2 mols of hydrogen, then to cancel out mols of hydrogen, divide by what is in the equation: so 23.2 mols H2 / 2 mols H2. Next, to get mols of H2O multiply that number by the mols of water in the equation.
this answer makes sense because as you can see in the equation, there are 2 H2:2 H2O, so the amounts should be the same.
hope this helps! make sure to practice because it is ESSENTIAL that you understand this, especially if you plan on taking ap chem. good luck! :)
Hi!
Magnets attract with opposite poles. The reason is the North pole of a magnet's magnetic lines (if that makes any sense) generally flow inwards, making it pulling in, and the South pole's magnetic lines flow outwards, pushing out. If you align two magnets with the same poles together, they will always repel, because they will be flowing in different directions.
However, if you align a north and a south pole together, they will work together, and attract.
Therefore, if you place two magnets randomly, and they're close enough, they'll align so that the north pole of one magnet faces the south pole of the other magnet, or choice A.
1.50 moles H20(6.02*10^23 molecules/1 mole)
9.03*10^23 molecules
