In any chemical compound, the elements are always combined in the same proportion by ___.?

charge

mass

volume

density

What is the wavelength of a wave with a velocity of 50 m/s and a frequency of 5 Hz?

5.00 of a certain Compound X, known to be made of carbon, hydrogen and perhaps oxygen, and to have a molecular molar mass of 128.

What happens when the threat of exposure to dirty air is reduced in a community? There is enough oxygen available for people's lungs to function normally The amount of indoor air pollutants released during a fossil fuel burn decreases There is a

How many moles of iridium are in 26.4 g of iridium? a. 1 mol b. 1.37 10-1 mol c. 5.06 103 mol d. 7.29 mol

The formation of a white cloud

What is the molality of a solution containing 100 grams of glucose (C6H12O6, molar mass = 180 g/mol) dissolved in 2.5 kg of water? 0.22 m 72 m 7200 m 40 m

A battery is constructed based on the oxidation of magnesium and the reduction of cu2+. the initial concentrations of mg2 + and cu2 + are 1.2*10-4 m and 1.44 m, respectively, in 1.0-liter half-cells. how long can the battery deliver 5.

A buffer solution is made that is 0.417 M in and 0.417 M in. If for is, what is the pH of the buffer solution? pH = Write the net ionic equation for the reaction that occurs when 0.120 mol is added to 1.00 L of the buffer solution.

BaCl2 (aq) + AgNO3 (aq) → Express your answer as a chemical equation. Enter noreaction if no precipitate is formed.

Make a list of physical changes and chemical changes that you observe or see effects of in the school