In the reaction 2H2 + O2-->2H2O how many hydrogen molecules are needed to produce two water molecules

What is the mass of 8.90 moles of magnesium chloride, MgCl2? Express your answer numerically in grams.

Will mark as brainlest! What is the wavelength of an electromagnetic wave that travels at 3 x 108 m/s and has a frequency of 60 MHz? (1 MHz = 1,000,000 Hz)

What type of bond exists between Sodium and Potassium?

Common brass is a copper and zinc alloy containing 37.0% zinc by mass and having a density of 8.48 g/cm3. A fitting composed of common brass has a total volume of 112.5cm^3. How many atoms of copper and zinc does the fitting contain?

What mass of sulfur would have precisely 4.7x10^22 atoms of sulfur?

In each row, the box under the compound that can reasonably be expected to be more acidic in aqueous solution, e. g. have the larger Ka. H2 TeO4 H2TeO3 HClO2 HClO HClO HBrO

You are doing chores to earn your allowance. For each chore you do, you earn $3.00. What is the independen variable?

As the solar system formed, most of its mass became concentrated in one part of it. What is that that part?

In the scientific process what is the purpose of the experiment A-to test the hypothesis B-to prove the hypothesis true C-to prove the hypothesis fake D-to turn the hypothesis into a theory

A sample of an unknown substance has a mass of 0.158 kg. If 2,510.0 J of heat is required to heat the substance from 32.0°C to 61.0°C, what is the specific heat of the substance?