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:
Word-Definition
Pure substance- 4
Matter- 2
Atom- 1
Molecule- 3
Element- 5
Answer:
The reaction is exothermic.
Yes, released.
The heat released is 4,08x10³ kJ.
Explanation:
For the reaction:
C₃H₈(g) + 5O₂(g) → 3CO₂(g) + 4H₂O(l)
The ΔH is -2220 kJ, As ΔH is <0, <em>The reaction is exothermic.</em>
As the reaction is exothermic, the heat of the reaction will be <em>released.</em>
The heat released in 81,0g is:
81,0g C₃H₈×
×
= <em>4,08x10³ kJ</em>
<em>-Using molar mass of C₃H₈ to convert mass to moles and knowing that there are released 2220 kJ per mole of C₃H₈-</em>
I hope it helps!
Answer:
Metal more reactive than non metal
Answer:
Energy is released.
Explanation:
When an electron absorbs energy, it moves up into an excited state. When it releases energy, it will return to the ground state.
