How many group and periods are there in modern periodic table

Sylvanite is a mineral that contains 28.0% gold by mass. how much sylvanite would you need to dig up to obtain 77.0 g of gold? explain how you got your answer and the steps you took. you

Brainliesttt me asap! the below reaction can be categorized as more than one type of reaction. which reactions are these, and what are the types of reactions?

What is the ph of a 0.0010 m hno3? 1.0 3.0 4.0 5.0