A 130.3 g piece of copper (specific heat 0.38 J/g･°C) is heated and then placed into 400.0 g of water initially at 20.7°C. The water increases in temperature to 22.2°C. What is the initial temperature (in °C) of the copper? (The specific heat of water is 4.18 J/g･°C).

How many moles of magnesium is 3.01 x10^22 atoms of magnesium?

What is the wavelength of a 3*10^12 hz infrared wave a 3*10^20m b 1* 10^4m c 3*10^-3m d 1*10^-4 m

You form water vapor by mixing oxygen and hydrogen at 730°c in a 5.4-liter container. this is the equation for the reaction: o2(g) + 2h2(g) → 2h2o(g). the partial pressure of oxygen before the reaction is 122.3 kilopascals, and there is excess hydrogen. how many moles of water are formed?