How to tell if a reaction is endothermic or exothermic by looking at it?

The combustion of propane (C₃H₈) produces 2220 kJ of energy per mole of propane consumed. How many grams of propane will be required to heat 67.0 gal of bathtub water from 25.0°C to 35.0°C if the process is 80.0% efficient? (1 gal = 3.

1. Define the terms "atomic number" and "atomic mass." 2. Explain how you can use both of these terms to find the number of protons, neutrons, and electrons in a neutral atom of Neon (Ne).

Rubidium is a soft, silvery-white metal that has two common isotopes, 85Rb and 87Rb with masses of 84.904 and 87.099 respectively. If the abundance of 85Rb is 72.2% and the abundance of 87Rb is 27.

What is the half-life of a 3 g sample of radioisotope that decayed to 0.75 g in 30 days?

If an atom has 8 valence electrons, how many electrons does it need to gain to achieve a stable electron configuration?

Solid lithium metal and diatomic fluorine gas react spontaneously to form a solid product. give the balanced chemical equation (including phases) that describes this reaction.

What is the best way to transform a chemical potential energy into internal kinetic energy?

A reaction starts with 20.0 grams of lithium hydroxide (LiOH) and produces 31.0 grams of lithium chloride (LiCl), what is the percent yield of lithium chloride (LiCl) ? * LiOH + KCl - LiCl + KOH A) 64.5% B) 88.6% C) 81.5% D) 92.8%

You aren't sure if your pH meter needs to be calibrated, so you put it in a buffer solution that has a known pH of 7. You take four separate readings of the solution with the pH meter. The meter reports the pH as 5.5, 8.6, 6.3, and 9.4.

Can you explain and read this equation 2Mg + 02 - - 2MgO