Is baking soda a element, compound or a mixture?

Which term refers to a property that depends only on the amount of a substance? ©@

How many oxygen atoms are there in 3.15 moles of hcl manganese (iv) oxide, mno2

Determine the ph of 0.10 m nh3 solution. nh3 is a weak base with a kb equal to 1.8 x 10-5 round answer to nearest whole number.