Which reaction is endothermic?

H2 (g) + ½ O2 (g) → H2O (g), ΔH = - 57.82 kcal

½N2 (g) + O2 (g) + 8.1 kcal → NO2 (g)

½N2 (g) + 3/2H2 (g) → NH3 (g) + 11.0 kcal

C (diamond) + O2 (g) → CO2, ΔH = - 94.50 kcal

Do atoms lend and borrow electrons from inner shells

Which activity is an example of poor personal hygiene

In the formate ion, hco2 - which of the atoms in the ion have pπ orbitals?

Explain why ice is able to float on water

A cube of aluminum (Cp = 0.897 J/g•K) has a temperature of 325 K. It is placed in a beaker of cold water. If the aluminum cools to 301 K as the water absorbs 815.7 J of heat, what is the mass of the cube?

Consider the following statements. A. Molecules of hot water have less kinetic energy than those of cold water. B. For most solids, solubility increases when temperature increases. C.

Which describes the fourth state of matter known as plasma? A It is a liquid containing nuclei and electrons. B It is a gas containing nuclei and electrons. C It is a liquid containing electrons created by fusion.

The process of using dna to produce complementary rna molecules is called

A substance contains 36.1 percent calcium and 63.9 percent chlorine by weight. What is the empirical formula of the given compound? A. CaCl B. Ca0.9Cl1.8 C. CaCl2 D. Ca2Cl4

A sample of bismuth weighing 0.687 g was converted to bismuth chloride by reacting it first with HNO3, and then with HCI, followed by careful evaporation to dryness. The mass of the bismuth chloride obtained was 1.032 g.