How can some stars be bright yet cool (and vice versa) ?

Newton's second law of motion uses the formula which states that a force will cause a mass to accelerate. (f = m • a. rewrite the formula to solve for a.

Classify each of the following properties as physical or chemical: A. Ice melts in the sun. B. Copper is a shiny metal. C. Paper can burn. D. A silver knife can tarnish. E. A magnet removes iron particles from a mixture.

Find the molar mass Na3PO4

Calculate the wavelength in nanometers of the light emitted by a hydrogen atom when it's electron falls from the n = 7 to the n = 4 principal energy level. Recall that the engergy levels of the H atom are given by En = - 2.

How many electrons are present in 4He2+? 1. 6 2. 4 3. 1 4. 2 5. 0 6. None of these 7. 3 8. 5

1 75 ml of lemon juice are added to 50 ml of water. What is the percent by vo of the solute?

How many moles of tungsten atoms are in 4.8 x 1025 atoms of tungsten?

At what speeds do you criuse down the track of a roller coaster

A sample of hydrogen gas is mixed with water vapor. The mixture has a total pressure of 755 torr and the water vapor has a partial pressure of 24 torr. What amount (in moles) of hydrogen gas is contained in 1.55 L of this mixture at 298 K?

Both equation I and II are balanced, but equation II is the correct way to write the balanced equation. Why do you think this is? (Hint: Think fractions.) I) 2 SnO2 + 4 H2 → 2 Sn + 4 H2O II) SnO2 + 2 H2 → Sn + 2 H2O