State two reasons why most apparatus are made of glass

When a match burns it's mass decreases. Is this a violation of the law of conservation of mass?

How many atoms of mercury are present in 3.4 cubic centimeters of liquid mercury? the density of mercury is 13.55 g/cc?

Caffeine has a molar mass of 195 grams per mole. The percent composition of its component elements is: carbon: 49.5 percent hydrogen: 5.1 percent nitrogen: 28.9 percent oxygen: 16.5 percent Find the empirical and molecular formulas of caffeine.

Describe the photoelectric effect and explain why it made modifications to the Rutherford model necessary.

Using the equations and enthalpy values provided, which mathematical expression can be used to determine the unknown enthalpy change represented by x?

What is the product? 3•[1 - 4 5 - 7] [3 - 12 15 - 21] [4 - 1 8 - 4] [3 12 15 21] [4 - 12 8 - 21]

A hormone is an organ that secretes chemical substances into the bloodstream.

Complete and balance the equation for the combustion of zns in excess oxygen? zns + ? o2→? zno + ? use no fractional coefficients. the number of moles and the formula of the product containing s are

What is the relationship between the units of measurement for the volume of a liquid and of a solid object?

1. Which of the following elements is a transition metal?