Three students are asked to discuss why the water only condensed on the upper half of the test tube. Select the student that employs correct scientific
reasoning
. Student 1: Water is left in the mouth of the test tube because carbon dioxide leaves first and
water is then left behind, this is due to the difference in the molar masses.
• Student 2: The water only condensed on the upper half of the test tube because the upper half
was cool enough to allow the phase change to occur.
• Student 3: As the carbon dioxide left the test tube it pushed the water vapor out.
O Student 3
OStudent 2
O Student 1

Voltaic cells produce a positive overall charge. what does this indicate? a. the reaction is likely to be endothermic. b. the reaction is spontaneous. c. the reaction is not likely to occur. d. the reaction is not spontaneous.

The table compares the number of electrons in two unknown neutral atoms. comparison of electrons atom number of electrons a 9 d 11 use this information to determine the number of valence electrons in the atoms. which of the following correctly compares the stability of tthe table compares the number of electrons in two unknown neutral atoms. comparison of electrons atom number of electrons a 9 d 11 use this information to determine the number of valence electrons in the atoms. which of the following correctly compares the stability of the two atoms? both are unreactive. both are highly reactive. a is unreactive and d is reactive. a is reactive and d is unreactive.

The characteristics of two different types of reactions are shown below: reaction a: electrons are gained by the atoms of an element. reaction b: protons are lost by the atom of an element. which statement is true about the atoms of the elements that participate in the two reactions? their identity changes in both reaction a and reaction b. their identity changes in reaction a but not in reaction b. their identity changes in reaction b but not in reaction a. their identity remains the same in both reaction a and reaction b.