A student tested a sample of carbon (C) by combining it with water. There was no reaction between the carbon and water. The student concluded that carbon must be a
group 18 element, since it was unreactive is this conclusion correct? Why or why not?

A. Yes Water would react with almost every element, except Group 18 elements
B. No. The carbon probably did react, but did not give off any signs or indications of a chemical
change
C. No. Just because carbon did not react with water, does not mean it wouldn't react with a
different compound
D. Yes. The student can make a reasonable conclusion based on one experiment.

Agroup of students is studying convection currents. they fill two identical balloons with the same amount of helium. one balloon is placed in a freezer and the other in an area with warm air. after 10 minutes, the balloons are released from a height of 1 meter. which of the following do the students most likely observe? a. the balloons both rise. the cold balloon is larger than the warm balloon. b. the balloons rise at the same rate. both balloons are the same size. c. the warm balloon expands and rises. the cold balloon shrinks and sinks. d. the cold balloon expands and rises. the warm balloon shrinks and sinks.

What layer of the atmosphere is directly above the troposphere?

What does a complete balanced chemical equation include? a. exothermic coefficients b. endothermic coefficients c. valence electrons d. molar coefficients