A powder and a liquid with total mass of 20 grams are combined in an open beaker. A reaction occurs, as indicated by the production of gas of bubbles. The final mass of solution is less than 20 grams. what best explains the difference in mass? A. Not all reactions obey the law of conservation of mass.

B. Mass escaped as a gas from the open container.

C. Some mass was consumed in the reaction.

D. The bubbles show that mass was added to the system.

During physical science, ms. greene challenged her students to produce an energy transformation. james and jill wrapped a 4-inch nail with a coil of fifty turns of wire. they connected one end of the coil to one terminal of a knife switch. they connected the other terminal of the knife switch to the battery. finally, they connected the end of the coil to the other terminal of the battery. james held the tip of a 1-inch nail near the flat end of the 4-inch nail. jill closed the knife switch quickly and then opened it. the 1-inch nail was pulled toward the 4-inch nail. what is the best explanation of why the nail moved? a) electrical energy was converted to mechanical energy in the 1-inch nail. b) the 4-inch nail became an electromagnet and the magnetic force attracted the 1-inch nail. c) the electric current in the 4-inch nail was converted to mechanical energy in the 1-inch nail. d) the 4-inch nail had a positive charge and the 1-inch nail had a negative charge. opposites attracted.

From 0 to 5 seconds john pushed a box 5 meters. from 5 to 10 seconds, paul pushed the same box another 5 meters. who did more work? a. john b. paul c. john and paul did the same amount of work.

Gordon is going for a run through the park, but it is cold outside. the low outside temperature could affect his personal safety.