Questions 1–3 refer to the following gases at 0°C and 1 atm. Which gas has an average atomic or molecular speed closest to that of N₂ molecules at 0°C and 1 atm?

• Ne

• Xe

• O₂

• CO

• NO

Tags

NGSS.HS-PS3-2

Questions 1–3 refer to the following gases at 0°C and 1 atm. Which gas has the greatest density?

• Ne

• Xe

• O₂

• CO

• NO

Questions 1–3 refer to the following gases at 0°C and 1 atm. Which gas has the greatest rate of effusion through a pinhole?

• Ne

• Xe

• O₂

• CO

• NO

Tags

NGSS.HS-PS3-2

Which gas has molecules with a pyramidal shape?

• H₂(g)

• HBr(g)

• H₂S(g)

• NH₃(g)

• BH₃(g)

Which gas is the slowest to effuse through a small opening at 25 degrees Celsius and 1 atm?

• H₂(g)

• HBr(g)

• H₂S(g)

• NH₃(g)

• BH₃(g)

Which of the following ions has the same number of electrons as Br⁻?

• Ca²⁺

• Cl⁻

• I⁻

• K⁺

• Sr²⁺

Tags

NGSS.HS-PS1-1

In solid methane, the forces between neighboring CH₄ molecules are best characterized as

• covalent bonds

• hydrogen bonds

• ionic bonds

• ion-dipole bonds

• London (dispersion) forces

Of the following electron configuration of neutral atoms, which represents an atom in an excited state?

• 1s²2s²2p⁵

• 1s²2s²2p⁶3s¹

• 1s²2s²2p⁵3s²

• 1s²2s²2p⁶3s²3p²

• 1s²2s²2p⁶3s²3p⁵

Tags

NGSS.HS-PS1-1

Which of the following is a nonpolar molecule that contains polar bonds?

• F2

• HCl

• CO2

• NH3

• CHF3

Which of the following shows the correct number of protons, neutrons, and electrons in a neutral cesium-134 atom?

• 134 protons, 55 neutrons, 134 electrons

• 79 protons, 55 neutrons, 79 electrons

• 55 protons, 79 neutrons, 79 electrons

• 55 protons, 79 neutrons, 55 electrons

• 55 protons, 55 neutrons, 55 electrons

Tags

NGSS.MS-PS1-1