A sample of gas has a pressure of 742 torr. What is the pressure in atmospheres?

742 torr= approximately 0.976 atm

Explanation:

Since we know that one atm= 760 torr, we can compute the following calculation:

(742 torr/1)*(1atm/760torr)=0.976316 atm

Remember sig figs (3) to round it to 0.976 atm

*=0.976316=0.976 atm

(torr cancels out and we're left with atm)

Hope this helps :)

"the periodic table is arranged in order of atomic number."

"you start with 15.67 g mgco3-xh2o, when heated and all the water is removed, you are left with 7.58 g mgco3 only.

therefore, you had 15.67 - 7.58 = 8.09g h2o  

moles of each :

7.58g mgco3 = ? moles = 7.58g / 83.4g/mole = 0.09moles  

8 09g h2o = ? moles = 8.09g / 18g/mole = 0.44moles  

molar ratio between the two by dividing both numbers by the smallest number :

0.09 / 0.09 = 1  

0.44 / 0.09 = 4.8  

mgco3-5h2o"