A compound contains 75% carbon and 25% hydrogen by mass. What is the empirical formula for this compound?
CH
C4H
CH4
C2H8

The comparison of the number of atoms in a copper coin the size of a penny with the number of people on earth is made to illustrate which of the following? a. that atoms are indivisible b. that atoms are very small c. that atoms are very large d. that in a copper penny, there is one atom for every person on earth

Which activity describes an application of topographic maps? check all that apply. recreation, such as camping and hiking engineering, such as the construction of roads and buildings science, such as mapping stars in the sky business, such as analyzing population centers science, such as analyzing surface features

Calculate the mass of 0.750 mol of the following substance. na3po4.