AP Chemistry

How many carbon atoms are contained in 2.8 g of C2H4 ?

• 1.2 x 10^23

• 3.0 x 10^23

• 6.0 x 10^23

• 1.2 x 10^24

• 6.0 x 10^24

Which of the following elements has the mass spectrum represented above?

• Nb

• Mo

• U

• Cf

Tags

NGSS.HS-PS1-8

When hafnium metal is heated in an atmosphere of chlorine gas, the product of the reaction is found to contain 62.2 percent Hf by mass and 37.4 percent Cl by mass. What is the empirical formula for this compound?

Tags

NGSS.HS-PS1-2

NGSS.HS-PS1-7

To gravimetrically analyze the silver content of a piece of jewelry made from an alloy of Ag and Cu, a student dissolves a small preweighed sample in HNO3(aq). Ag+(aq)and Cu2+(aq) ions form in the solution. Which of the following should be the next step in the analytical process?

• Centrifuging the solution to isolate the heavier ions

• Evaporating the solution to recover the dissolved nitrates

• Adding enough base solution to bring the pH up to 7.0

• Adding a solution containing an anion that forms an insoluble salt with only one of the metal ions

The mass percent of carbon in pure glucose, C6H12O6, is 40.0 percent. A chemist analyzes an impure sample of glucose and determines that the mass percent of carbon is 38.2 percent. Which of the following impurities could account for the low mass percent of carbon in the sample?

• Water, H2O

• Ribose, C5H10O5

• Fructose, C6H12O6, an isomer of glucose

• Sucrose, C12H22O11

The effective nuclear charge experienced by the outermost electron of Na is different than the effective nuclear charge experienced by the outermost electron of Ne. This difference best accounts for which of the following?

• Na has a greater density at standard conditions than Ne.

• Na has a lower first ionization energy than Ne.

• Na has a higher melting point than Ne.

• Na has a higher neutron-to-proton ratio than Ne.

• Na has fewer naturally occurring isotopes than Ne.

Tags

NGSS.HS-PS1-1

Write the ground-state electron configuration of the O−2 ion?

• 1s2 2s2

• 1s2 2s2 2p4

• 1s2 2s2 2p6

• 1s2 2s2 2p5 3s2

Tags

NGSS.HS-PS1-1

NGSS.HS-PS1-2

The photoelectron spectra for H and He are represented above. Which of the following statements best accounts for the fact that the peak on the He spectrum is farther to the left and higher than the peak on the H spectrum?

• He has an additional valence electron in a higher energy level than the valence electron in H

  .

• He has a greater nuclear charge than H and an additional electron in the same energy level.

• He has a completely filled valence shell in which the electrons are a greater distance from the nucleus than the distance between the H nucleus and its electron.

• It takes longer for the electrons in He to be removed due to the higher nuclear mass of He.

Tags

NGSS.HS-PS1-1

NGSS.HS-PS1-2

A sample containing atoms of C and F was analyzed using x-ray photoelectron spectroscopy. The portion of the spectrum showing the 1s peaks for atoms of the two elements is shown above. Which of the following correctly identifies the 1s peak for the F atoms and provides an appropriate explanation?

• Peak X, because F has a smaller first ionization energy than C has.

• Peak X, because F has a greater nuclear charge than C has.

• Peak Y, because F is more electronegative than C is.

• Peak Y, because F has a smaller atomic radius than C has.

Tags

NGSS.HS-PS1-1

NGSS.HS-PS1-2

Based on the ionization energies of element X given in the table above, which of the following is most likely the empirical formula of an oxide of element X?

• XO2

• X2O

• X2O3

• X2O5

Tags

NGSS.HS-PS1-1

NGSS.HS-PS1-2