Two substances each have a temperature of 23 degrees Celcius. After they are combined the temperature rises to 27 degrees Celcius. What evidence proves a chemical reaction occurred?

Where are atoms that tend to gain electrons located in the periodic table of the elements? A. on the left side B. on the right side C. in the middle columns D. starting on the fourth row

An English unit used in pharmaceutical work is the grain (gr). There are 15 grains in 1 gram. An aspirin tablet contains 5.0 gr of aspirin. A 145 lb person takes two aspirin tablets.

Which type of bonding is characterized by overlapping orbitals that allow outer electrons of atoms to move about freely throughout the entire lattice? A covalent B multiple C ionic D metallic

If the length, width, and height of a box are 8.00 cm, 6.75 cm and 3.50 cm, respectively, what is the volume of the box in units of milliliters and liters?

Which of the following correctly describes the general process of coal mining and refining? Select one: a. Coal is mined, washed, dried, and then separated from rock particles. b. Coal is mined, dryed, and crushed. c.

Carbon-14 has a half-life of 5730 years. In a plant fossil, you find that the 14C has decayed to 1/4.00 of the original amount. How long ago was this plant alive?

Balance this equation---> Fe (s) + O2 (g) - - - >FeO (s) (s) = solid (g) = gas

During an endothermic phase change, what happens to the potential energy and the kinetic energy?

What is the difference between pure substance, element, and compund

Butane gas is used as the fuel in disposable lighters. It burn in oxygen to form carbon dioxide gas and water vapor. What mass of carbon dioxide is produced when 53.3 g of butane is burned in 103.9 g of oxygen