Chemistry NCFE 2018-19 #29-40

29) What can the student conclude about the experiment?

• A chemical reaction occurred because new atoms were created.

• A chemical reaction occurred because a new substance was formed.

• The popping sound provided evidence that the acid changed physical states.

• The popping sound provided evidence that the magnesium atoms were

  destroyed.

Tags

NGSS.MS-PS1-2

30) How many O₂ particles are in 2.50 moles of O₂ at Standard Temperature and Pressure (STP)?

• 4.15 × 10²² particles

• 2.41 × 10²³ particles

• 5.02 × 10²³ particles

• 1.51 × 10²⁴ particles

Tags

NGSS.HS-PS1-7

31) Why does an increase in temperature usually increase the rate of a chemical reaction?

• because the activation energy of the reaction increases

• because the surface area of reacting particles increases

• because the proper orientation of reacting particles improves

• because the number of effective collisions between reacting particles increases

Tags

NGSS.HS-PS1-5

32) Which action will cause the reaction to shift to the left?

• heating the flask with a hot plate

• placing the flask in an ice bath

• removing H₂O from the flask

• adding CO to the flask

Tags

NGSS.HS-PS1-5

NGSS.HS-PS3-4

33) Which temperature has the greatest concentration of product Z?

• 200 K

• 300 K

• 400 K

• 500 K

Tags

NGSS.HS-PS1-5

NGSS.HS-PS1-6

34) How would the conditions of equilibrium be affected by decreasing the concentration of substance W?

• Substances X and Y would react to replace substance W, and the position of equilibrium would shift to the right.

• Substances Y and Z would react to replace substance W, and the position of equilibrium would shift to the left.

• This would increase pressure, causing only substance Y to replace substance W and shifting the equilibrium to the right.

• This would decrease temperature, causing only substance Z to replace substance W and shifting the equilibrium to the left.

Tags

NGSS.HS-PS1-5

35) A solution has a pOH of 12. Which best describes the solution?

• It has a pH of 2 and is a base.

• It has a pH of 12 and is a base.

• It has a pH of 2 and is an acid.

• It has a pH of 12 and is an acid.

36) A student describes a liquid as feeling slippery. The student places red litmus paper into the liquid, and the paper turns blue. What can the student conclude from these observations?

• The substance is likely a nonmetal.

• The substance is likely a metal.

• The substance is likely a base.

• The substance is likely an acid.

37) In the titration, 15.0 mL of CsOH solution is neutralized by 38.2 mL of 0.250 M HBr solution. What is the molarity of the CsOH solution?

• 0.0982 M

• 0.637 M

• 1.36 M

• 10.2 M

Tags

NGSS.HS-PS1-7

38) What type of solution is formed when solid sodium hydroxide (NaOH) is dissolved in water?

• an electrolytic solution, because NaOH will dissociate into ions

• an electrolytic solution, because NaOH will not dissociate into ions

• a nonelectrolytic solution, because NaOH will dissociate into ions

• a nonelectrolytic solution, because NaOH will not dissociate into ions

Tags

NGSS.HS-PS1-3