How many pairs of electrons do the two oxygen atoms in an oxygen molecule share with each
other? explain your answer.

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

Asample of aluminum foil contains 8.60 × 1023 atoms. what is the mass of the foil?

Freezing and boiling are endothermic processes. this means that these processes absorb energy from their surroundings in order to occur. use this information and the data you collected in the phase change gizmo to describe what happens to the temperature of water when you boil it, then explain why this result occurs.