They are a relatively recent invention.
I hope it was helpful for you.
Answer:
298.9 million years ago - 251.902 million years ago
Explanation:
It might be in the 2011 Earth Science Review Packet so maybe go check that out
I think it is aluminum oxide
Answer: The new pressure of the gas in Pa is 388462
Explanation:
Combined gas law is the combination of Boyle's law, Charles's law and Gay-Lussac's law.
The combined gas equation is,

where,
= initial pressure of gas at STP = 
= final pressure of gas = ?
= initial volume of gas = 700.0 ml
= final volume of gas = 200.0 ml
= initial temperature of gas = 273 K
= final temperature of gas = 
Now put all the given values in the above equation, we get:


The new pressure of the gas in Pa is 388462
Answer:
3. The temperatures of the two substances equalize.
Explanation:
- As two objects at different temperatures are placed in contact, heat is transferred from the warmer to the cooler object until the temperature of the two objects be the same.
- The amount of heat that is transferred from the warmer object is equal to the amount of heat that is transferred into the cooler object.
- This is in agreement with the law of conservation of energy.
- <em>So, the right choice is: 3. The temperatures of the two substances equalize. </em>
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