In a calorimeter, 20 g of ice absorbs heat with an enthalpy of fusion of 334 J per g. What is the heat absorbed? q equals m delta H subscript f end subscript Substance C in joules per gram dash degree centigrade Water (ice) 2.05 Iron 0.46 Aluminum 0.90 Gold 0.13 Copper 0.39 Ammonia (liquid) 4.70 Ethanol 2.44 Gasoline 2.22 Water (liquid) 4.18 Water (vapor) 2.08 Air open parentheses 25 degrees C close parentheses 1.01 Oxygen 0.92 Hydrogen 14.30 options: 334 J 6.68 J 3.34 kJ 6.68 kJ

Part of molten rock at mid-ocean ridges

Agroup of students is studying convection currents. they fill two identical balloons with the same amount of helium. one balloon is placed in a freezer and the other in an area with warm air. after 10 minutes, the balloons are released from a height of 1 meter. which of the following do the students most likely observe? a. the balloons both rise. the cold balloon is larger than the warm balloon. b. the balloons rise at the same rate. both balloons are the same size. c. the warm balloon expands and rises. the cold balloon shrinks and sinks. d. the cold balloon expands and rises. the warm balloon shrinks and sinks.

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