A student is analyzing an unknown substance. The substance is solid at room temperature, but when heated only slightly, it melts. It boils when placed over a flame for more than a few seconds. The student dissolves the substance in water and finds the solution does not conduct electricity. Based on the experimental evidence, how should the student categorize the molecules that make up this substance? A:ionic compounds

B:transition metals

C:radioactive

D:covalent compounds

7. what temperature is need to just dissolve 50 g of nh4cl in 75 g of water? '

What is the binding energy of a nucleus that has a mass defect of 5.81*10-^29 kg a 5.23*10-^12 j b 3.15* 10^12 j c 1.57*10-3 j d 9.44*10^20 j

Under what conditions will a gas be most likely to exhibit the ideal gas properties predicted by the ideal gas law? 1)high pressures and high temperature, because particles are forced closer together with higher kinetic energy, so intermolecular forces of attraction are weaker 2)high pressure and low temperature, because particles are forced closer together and moving slower, so the volume of the particles is less significant 3) low pressure and high temperature, because particles are spread farther apart and moving faster, so the intermolecular forces of attraction are weaker 4)low pressure and low temperature, because particles are spread farther apart with lower kinetic energy, so the volume of the particles is less significant