Is Helium a compound, element, or. mixture

Which of the following is the best example of erosion? A. Sediment piling up at the mouth of a river B. Plant roots growing through concrete and splitting it C. Waves carrying sand away from a beach D.

1. A window washer does not want to change her position. What does she want the forces acting on her to be? A. small B. large C. balanced D. unbalanced 2. When an object that is moving slows down, which action must be occurring? A. balanced forces B.

Why are all of the substances on the periodic table classified as elements?

What will occur if solution A containing 400 mosmol/L nonpenetrating solute is separated by a biological membrane from solution B containing 600 mosmol/L nonpenetrating solute?

A 8390 g/hr stream of liquid methyl alcohol, also called methanol, (CH_3OH) at 6.20 atm and 24.0 degree C was held at constant pressure, vaporized and brought to 337.0 degree C.

What are the building blocks

If the specific heat of copper is 0.711 J/g•°C, how much copper would it take if the heat given off is 54.85 calories and the temperature change is 205°C.

Why is it is difficult to compress a liquid? a. liquid takes the shape of its container. b. the liquid particles flow away when compressed. c. liquid becomes solid when compressed. d. the liquid particles are very close together.

A mixture of two compounds, a and b, was separated by extraction. after the compounds were dried, their masses were found to be: 105 mg of compound a and 91 mg of compound b. both compounds were recrystallized and weighed again.

What are the five types of chemical reactions?