Blog

(01.07 LC) A piece of metal with a length of 1.42 cm was measured using four different instruments. Which of the following measurements is the most accurate?

(02.03 MC) An electron is present at an energy level with an energy of 16.32 x 10−19 J. During a transition to another level, 5.4 x 10−19 J of energy was absorbed. Which of the following is true about the present state of the electron?

(01.04 LC) It was observed that the atoms of a substance had so much energy that it separated the electrons and protons of the atom. What is most likely the state of matter of the substance?

(01.02 MC) Dan used the following method to convert 27.7778 cm/s to km/h.(1 km = 100,000 cm and 1 s = 0.000277778 h)What is the error in Dan’s conversion method?

(02.01 MC) Which of the following explains how one of the postulates in John Dalton’s atomic theory was later subjected to change?

(02.03 MC) An electron is present at an energy level with an energy of 5.44 x 10−19 J. After a second, the electron is present at an energy level with energy, 2.4 x 10−19 J. What most likely happened during the transition?

(01.07 HC) A student collected the data shown in the table below during an experiment. Liquid Characteristics Liquid Characteristics Boiling Point Freezing Point Color Toxicity Mercury 357 °C −39 °C shiny silver gray hazardous if tube is broken Alcohol 78 °C −115 °C colorless relatively non-hazardous Based on the data, which of the following conclusions can be made about the use of mercury and alcohol thermometers?

(02.01 MC) Which of the following explains how one of the postulates in John Dalton’s atomic theory later became robust knowledge?

(01.03 LC) What happens to the average kinetic energy of the molecules of a warm substance when the temperature of the substance is slightly decreased?

(02.01 MC) Which of the following explains how one of the postulates in John Dalton’s atomic theory was later strengthened?