Most Missed Chemistry Exam Questions

Steam_________

Steam is a water in the gas stage so it is just H₂0 which is all compound which is a pure substance

A snowball at -12°C, melts when you hold it in your hand and reaches body temp, 32°C. Explain HOW the energy is transferred between the snowball and the hand at the particle level

Endothermic: ↑T...↑ek...↑vel..↑#of force of collisions...↑spacing...↑V(until Pin=Pout) Constant: P and N

Which flask contains particles with the highest velocity?

Flask A b/c it has the highest velocity b/c it has the lowest amu which means there is more space for the particles to collide so their velocity is the highest velocity= movement of particle

Identify the BEST sentence to describe the relationship shown in the graph

None of the above describes and explains the relationship in the graph, the correct answer is as time increases mass decreases b/c the particles are released into the air (They are not destroyed, they just have time to exist the system)

A student determines the mass of sliver sample and calcualtes 1.20g, 1.92g, 2.01g and 2.88g. The correct value is 2.01g. Which statement concurring the results is correct?

Poor precision and accurate results. Accurate result b/c one of this answers is the actual correct answer. Not precise because he has four completely different answers that are not close to each other at all

What is the importance of the Kelvin scale?

The pressure at absolute zero is zero kilopascal and particles are still moving at zero celsius. Even when temp is 0° there is still ek, and collisions also have pressure. In kelvin the pressure is 0° b/c there's no ek or collisions.

Liquid water is being warmed in a pan on a stove. The burner on the stove is set on "LOW". Eventually the water boils. While the water is boiling the burners turned on the "HIGH" setting. What happens to the temperature of the liquid water?

The temp remains the same it would just get to that temp faster all water boils at the same temp.

Consider three 1-L flasks, which are sealed, at the same temp and pressure. Flask A contains H₂ gas (2.0 amu) flask B contains NO₂ gas (46 amu), and flask C contains Xe gas (131 amu)

They are identical b/c the Volume, temp and pressure of the flasks are all = which means that the # of particles must also be = for all the flasks because of avogadro's law (If 3 of the P,V,n, and T are the same and so is the last one)

When equal masses of the following samples are given equal amount of heat, the temperature increase observed in ach is indicated is below. Which material gas the largest specific heat?

Water at 2°C b/c water particles are less dense there needs to be more volume to the mass of metals os there's more potential energy so the amount of energy required to increase the T, ek (etc) is a lot larger so water has the largest specific heat capacity be it requires more energy

The density of the diagram A above would change if

the box were melted, b/c in order for it to melt the box you need to apply heat which temp and volume would allow more space between particles which would change the density of the box.