Aballoon has a volume of 1.34 liters with 2.00 moles of helium gas. how many moles of helium gas must be added to get the volume to 7.00 liters.

What element breaks down into yttrium-90?

Three cards with holes are arranged in a straight line. a light is shined through the first card’s hole and travels through all three cards. what does this tell you about light rays? a) that light is reflected b) that light is refractive c) that light travels in a straight line d) that light does not travel in a straight line

Which of these is not an example of chemical weathering? a. iron-rich mineral rusting b. feldspar turning into clay c. limestone reacting with acid d. granite breaking up into sand