AP Chemistry Unit 1

Which element is represented by this PES graph?

• argon

• potassium

• calcium

• scandium

Tags

NGSS.HS-PS1-1

The photoelectron spectra above show the energy required to remove a 1s electron from a nitrogen atom and from an oxygen atom. Which of the following statements best accounts for the peak in the upper spectrum being to the right of the peak in the lower spectrum?

• Nitrogen atoms have a half-filled p subshell.

• There are more electron-electron repulsions in oxygen atoms than in nitrogen atoms.

• Electrons in the p subshell of oxygen atoms provide more shielding than electrons in the p sub shell of nitrogen atoms.

• Nitrogen atoms have a smaller nuclear charge than oxygen atoms.

Answer explanation

"Nuclear charge" = charge of the nucleus. A greater nuclear charge will result in a greater attraction to the 1s electrons, and therefore more energy will be required to remove those electrons.

Tags

NGSS.HS-PS1-1

NGSS.HS-PS1-2

As you move down the periodic table atoms get bigger.  This is because ____________.

• The atoms have more mass.
• The atoms have more protons.
• The atoms have more energy levels
• The atoms have more nuetrons

Tags

NGSS.HS-PS1-2

Which one has the largest radius?

• Lithium (Li, atomic #3)
• Boron (B, atomic #5)
• Neon (Ne, atomic #10)
• Nitrogen (N, atomic #7)

Tags

NGSS.HS-PS1-1

What is the molar mass of Hydrogen Peroxide (H₂O₂)?

• 48 g/mole
• 34.02 g/mole
• 36.5 g/mole
• 35.5 g/mole

How many moles are in 16.94g of water?

• 16.94 mol H₂O
• 0.9401 mol H₂O
• 305.3 mol H₂O
• 1.063 mol H₂O

Tags

NGSS.HS-PS1-7

What is the mass in grams of 5.90 mol C₈H_18?

• .0512 g
• 19.4 g
• 673 g
• 389 g

Tags

NGSS.HS-PS1-7

Which pair has the same empirical formula?

• NaCrO₄ and Na₂Cr₂O₇
• C₂H₄O₂ and C₆H₁₂O₆
• C₃H₆O₃ and C₂H₆O₂
• CH₄ and C₂H₆

A compound consists of 72.2% magnesium(Mg) and 27.8% nitrogen(N) by mass. What is the empirical formula?

• Mg₄N₃
• MgN₂
• Mg₃N₂ 
• MgN

Tags

NGSS.HS-PS1-7

2.40 g of an explosive, J, contains 0.473 g of nitrogen. J also contains 33.8% carbon and 1.41% hydrogen by mass. The remainder of J is oxygen.

What is the empirical formula of J?

• C₄HNO₂

• CH₂N₂O

• C₂HNO₂

• CHNO