A scientist measures the heart rates of 30 students from the same class before and after they run for different amounts of time. The experimental set up is
shown below:
• Group 1 had ten students who ran one lap.
• Group 2 had ten students who did not run at all.
• Group 3 had ten students who ran two laps.
Group 4 had 30 students from another class whose heart rates were
not measured.
Which group is the control in this experiment?
A. Group 1 from this class
B. Group 2 from this class
C. Group 3 from this class
D. Group 4 from another class

13. calculate the initial concentration (before precipitation) of carbonate ions after the addition of each 0.05 ml of solution b to the 1.00 l beaker of solution a. divide the work among group members and write the answers in the table in model 3. assume the volume change as solution b is added is negligible. 14. notice the initial concentrations of zn2+ - and cu2+ in the table in model 3. a. explain how these were obtained from the data in model 2. b. as solution b is added and precipitates form, do these initial concentrations change? 15. use the data in model 2 to indicate the presence of precipitate (either znco3 or cuco3) after each 0.05 ml addition of solution b in model 3. 16. use the initial concentrations of carbonate ions and zinc ions to calculate the reaction quotient, qsp for the zinc carbonate scenarios in model 3. divide the work among group members and write the answers in the table in model 3. 17. use the initial concentrations of carbonate ion and copper(ii) ions to calculate the qsp for the copper(ii) carbonate scenarios in model 3. divide the work among group members and write the answers in the table in model 3.

What is the percent by mass of oxygen in fe2o3

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.