How many grams are contained in 1.38 moles of calcium?

The compound methyl butanoate smells like apples. its percent composition is 58.8% c, 9.9% h, and 31.4% o. what’s the empirical formula ?

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.

If a gas has an initial pressure of 101kpa and a volume of 10l, then it expands to a volume of 20l, what is the new pressure?