4. If 14.7 g of calcium is placed in 11.5 g of water, what mass of hydrogen gas is produced?
__ Ca + __ H2O → __ Ca(OH)2 + __ H2
please show work

Aradio signal from a gps satellite take only about 0.067 seconds to reach a gps reciever. if the speed of light is about 300,000km/s, then approximately how far away is the reciever from from the satellite?

Abeaker with 2.00×102 ml of an acetic acid buffer with a ph of 5.000 is sitting on a benchtop. the total molarity of acid and conjugate base in this buffer is 0.100 m. a student adds 4.70 ml of a 0.360 m hcl solution to the beaker. how much will the ph change? the pka of acetic acid is 4.740.

Give one example of a pure (exact) number and of an estimated (measured) number.