When you rub a match against a rough surface, fire results, giving off light and heat. The law of conservation of energy says that energy cannot be created. How can you explain the fire seeming to come from nowhere?

Knowledge of atomic structure has evolved over time. Thomson discovered that atoms contain electrons, Rutherford discovered that most of the mass of an atom is concentrated in its center, and Bohr discovered that electrons orbit the nucleus.

The visible spectrum for a colored solution has a maximum absorbances around both 440 nm and around 600 nm and a minimum absorbance between 510 and 540 nm. What is the color of the solution?

An object with a density of 1.7 g/ml will float in water True or False

The discovery well in the Splunge (Mississippian-Carter) Field was completed in 1973. As of January 1985, the field had 16 wells which had produced a total of 623,000 Mscf, 43 bbl of water, and no oil.

What is the element sulfur classified as

56 Explain, in terms of atomic structure, why the elements in Group 2 have similar chemical properties. 131

What must molecules do to react? a. Molecules must heat up b. Molecules must collide c. Molecules must expand to fill their container d. Molecules must interact with a catalyst

How many pictograms are in a gram?

Which type of signaling pathway uses second messengers because the hormone cannot pass through the plasma membrane? a.) amino acid based b.) lipid based

Why are the gases in the troposphere layer denser than the gases in the other layers?