Answer:
Classifying stars according to their spectrum is a very powerful way to begin to understand how they work. As we said last time, the spectral sequence O, B, A, F, G, K, M is a temperature sequence, with the hottest stars being of type O (surface temperatures 30,000-40,000 K), and the coolest stars being of type M (surface temperatures around 3,000 K). Because hot stars are blue, and cool stars are red, the temperature sequence is also a color sequence. It is sometimes helpful, though, to classify objects according to two different properties. Let's say we try to classify stars according to their apparent brightness, also. We could make a plot with color on one axis, and apparent brightness on the other axis, like this:
Explanation:
<h2>Answer:</h2>
Rutherford's models
<h2>Explanations:</h2><h2>What is the electron cloud model?</h2>
There are known as the region where electrons are found especially in the nucleus.
According to the five basic atomic models which have contributed to the structure of the atom itself, the Rutherford's models of the atom include a structure that is mostly made of empty space compared to thomson that proposed the plum pudding model of the atom
Answer: So if you had 570 cm of ribbon, then 570%2F8.5=67.05 which means that about 67 students can do the experiment (round down to the nearest whole number).
Explanation: If you had 8.5 cm of ribbon, then only 8.5%2F8.5=1 student can do the experiment. If you had 17 cm of ribbon, then 17%2F8.5=2 students can do the experiment.
Http://www.chem4kids.com/files/elem_pertable.html this should help.
<u>Answer:</u>
2.0158 grams
<u>Explantion:</u>
We are to find the mass of the hydrogen atoms in 1 mole of water.
We know that the formula of water is: 
We can see, from the above mentioned formula, that water has 2 hydrpgen atoms.
From the periodic table, we get to know that Hydrogen has an atomic mass of 1.00794 grams.
As there are 2 atoms of hydrogen in water so 
grams is the answer
