8. (WCSP24.) Heavy metals, such as calcium, can be extracted from water by a precipitation reaction.   Hard water has a Ca2+ ion concentration around 4.24 x 10-3 M.   When hard water is mixed with a solution of soda ash (sodium carbonate, Na2CO3), the calcium ions react to form a precipitate and the water is now “softened.”  The precipitate can be removed by filtration. a.  (8 points) Write the complete balanced equation and the net ionic equation that occurs when Ca2+ and sodium carbonate react. Circle the precipitate. b.  (6 points) A 1000 mL soda ash solution was prepared with 5.0 g of sodium carbonate (MW = 106 g/mol).  Calculate the concentration (in M) of the sodium carbonate in the solution.  Calculate the concentration of sodium ions Enter the concentration of sodium ions below.

For which of the following reactions would ΔHf = ΔHrxn for the formation of HCl? (WCSP24)  

Suppose the cashier’s algorithm is optimal for denominations

Recall the Scheduling Min Lateness problem. Define lateness of a task as max(0, finish time – due date). T/F: The earliest due date first algorithm produces the optimal solution when we want to minimize the sum of the lateness of the tasks instead of the maximum.

A minimum bottleneck spanning tree (MBST) is a spanning tree that minimizes the maximum weight of any edge of the spanning tree.  T/F: A spanning tree is a MST if it is a MBST.

Hemorrhage from small arterial vessels in the basal layer of the decidua may cause which of the following conditions?

Which of the following pregnant women is at highest risk for having an infant with congenital anomalies? 

Which kind of email attacks has the goal to trick the recipients into clicking a link that leads to a fake and malicious website?

Search engines like Google and Yahoo!, social media like Facebook and Twitter, and retailers like Amazon and eBay fall under which ICT Industry?

In Microsoft Edge, a favorite is another name for which of the following?