Which expression represents a reaction rate?

Why does a leak in a car tire (at constant temperature) decrease the pressure of the tire? A) It removes kinetic energy from the system. B) The number of molecules decreases. C) The temperature decreases. D) The volume decreases.

How many ions are present in (NH4) 2CO3? ... ?

In which orbital does an electron in a bromine atom experience the smallest?

Why do scientists sometimes discard theories?

Name 3 natural carbon sources

Which element has an ion that is smaller than an ion calcium? Potassium, strontium, cesium, magnesium

A peregrine falcon can travel 537,600 furlong/fortnight. A race car travels 212ft/s. A spider can jump with a maximum velocity of 9,000,000 cm/hr. Which travels the fastest?

how many energy levels (shells) does an atom of oxygen have? How do you know this by looking at the periodic table?

A student needs to use 0.575 moles of sodium chloride in an experiment. How many grams should he mass out?

Which of the following seperation methods is used to seperate plant pigments? Filtration, Chromatography, fractional distillation, simple distillation?