December 21 is the first day of winter in the northern hemisphere. what season is it in the southern hemisphere? a. beginning of winter b. beginning of spring c. beginning of summer d. beginning of autumn (fall)

The rules of engagement (roe) working group is often used to (select all that apply.)

Calculate - analysis of compound composed of iron and oxygen yields 174.86 of fe and 75.14g of o. what is the empirical formula for this compound?

Which of the following is most likely true about water in chemical systems? a) water dissolves nonpolar ionic compounds. b) water dissociates ionic compounds. c) water dissociates covalent molecules. d) water dissolves nonpolar covalent substances.