The universal gas constant is 8.31451 J/K · mol. Calculate the change in internal energy of 7 mol of helium gas when its temperature is increased by 4.9 K. Answer in units of J.

There are weak or strong attractive forces between atoms of liquids with a high viscosity

The free body diagram shows a box being pulled to the left up a 25-degree incline. the magnitude of the normal force is

Ateacher gives students four liquids commonly found in the kitchen - vinegar, apple juice, dish detergent, and milk - and ph indicator strips, which measure acidity. the teacher asks the students to put the liquids in order from most acidic to most basic. what type of investigation could the students conduct to determine the correct order for the liquids?