Which processes represent one chemical change

and one physical change?

(1) freezing and melting

(2) freezing and vaporization

(3) decomposition and melting

(4) decomposition and combustion

A train travels 74 kilometers in 3 hours, and then 73 kilometers in 2 hours. What is its average speed? km/hr

A 5-column table with 2 rows. Column 1 is labeled number of protons, with entries A and D; column 2 is number of neutrons, with entries 7 and E; Column 3 is atomic number, with entries B and 26;

5. for the following measurements is expressed to three significant figures? a) 0.007 m b) 7077 mg c) 7.30 x 10^-7 km d) 0.070

What is the first thing you notice about a person?.-_-

Describe the physical properties of gold.

A noncompetitive inhibitor. binds to the active site of an enzyme a. b. increases the rate of enzyme action alters the primary structure of the enzyme c. d. none of these

True or false? The radioactive wastes produced by nuclear fission remain dnagerous for dozens of years

Determine the number of moles of Krypton contained in a 3.25 liter gas tank at 5.80 atm and 25.5 °C.

In the reaction 2co (g) + o2 (g) â 2co2 (g), what is the ratio of moles of oxygen used to moles of co2 produced? select one:

A log's mass is 5 kg. After burning, the mass of the ash is 1 kg. Explain what may have happened to the other 4 kg of mass.