The rock record indicates that photosynthesis began on Earth about 3.5 million years ago.

a. True

b. False

Place the elements below in order of decreasing ionization energy. Aluminum (Al) Chlorine (Cl) Magnesium (Mg) Sulfur (S)

How might earth's atmosphere be compared to human skin?

Which activities describe the use of technology in science? Check all that apply. looking at cells through a microscope viewing stars through a telescope observing a plant with the unaided eye creating a blank data table by hand in a notebook

Which of these choices Is a physical property that does not change when the size of the sample changes?

8. Ascorbic acid (Vitamin C) cannot be stored in the body, so it must be supplied in the diet. It is a C, H, O compound. If 7.75 g of Vitamin C is combusted in excess oxygen, it yields 11.62 g of CO2 and 3.17 g of water.

What is anisotropy. Explain briefly with example.

Which is measured using a calorimeter

5) Solid lithium metal is added to an aqueous solution of magnesium chloride forming lithium chloride solution and solid magnesium a. If you begin the reaction with 15.0 g of lithium and 25.

Which element easily loses one electron to form a positive ion? A. Magnesium (Mg) B. Lithium (Li) C. Nitrogen (N) D. Fluorine (F)

What is an indication a chemical reaction has occurred? A.) Formation of gas B.) Boiling of a substance C.) Melting of a substance D.) Freezing of a substance