1-There are 18 volcanoes in the US with the potential to erupt again, all of them in Alaska, Hawaii and the West Coast states.
2-Rubies and sapphires are actually the same mineral - corundum. The basic chemical formula of corundum is Al2O3, but traces of iron stain the mineral red (ruby) while traces of chromium or titanium stain the mineral blue (sapphire).
3-Rubies, sapphires and emeralds are all more rare than diamonds.
4-Not all diamonds are transparent. They come in a variety of colors (called "fancies"), including yellow, green, blue, orange, brown ("champagne"), purple, grey, black (called carbanado, recently shown to be meteroic), milky white, pink, and red. Red is by far the rarest.
5-Antacids taste like chalk because they ARE chalk, a.k.a. calcium carbonate.
Hope this helps, Give a thanks ! Haha
<span> A compound <span>lens microscope. </span></span>
Answer:
0.714 liter.
Explanation:
Given:
The balloon initially has a volume of 0.4 liters and a temperature of 20 degrees Celsius.
It is heated to a temperature of 250 degrees Celsius.
Question asked:
What will be the volume of the balloon after he heats it to a temperature of 250 degrees Celsius ?
Solution:
By using:

Assuming pressure as constant,
V∝ T
Now, let K is the constant.
V = KT
Let initial volume of balloon ,
= 0.4 liter
1000 liter = 1 meter cube
1 liter = 
0.4 liter = 
And initial temperature of balloon,
= 20°C = (273 + 20)K
= 293 K
Let the final volume of balloon is 
And a given, final temperature of balloon,
is 250°C = (273 + 250)K
= 523 K
Now,
= 

= 

Dividing equation 1 and 2,

K cancelled by K.
By cross multiplication:

Now convert it into liter with the help of calculation done above.

Therefore, the volume of the balloon be after he heats it to a temperature of 250 degrees Celsius is 0.714 liter.