Question

The NaOH used in this lab should have been 0.1M, since you were to make it as such (see Step 15 in lab document). Compare your standardized average molarity of NaOH in this lab to 0.1M. How do the values compare? How close was your NaOH dilution to actually being 0.1M NaOH? Calculate your percent error against the average standardized value from this lab. (You must show all work to receive credit.)

step 15- Prepare an aliquot (fancy chemical term for a portion from a larger whole) of 15.0 mL of 0.1 M NaOH. Notice that you only have 0.2 M NaOH in your lab kit, so you will need to make a dilution, if you didn’t already do so in a previous lab. To do this, very carefully follow the instructions in the “Before You Start” section on p. 17 in the eScience Student Lab Manual. The procedure for making the dilution is under the heading “Sodium Hydroxide” near the middle of the page. Again, if you already made this dilution, DO NOT dilute your dilution! Just use what you already made (0.1 M NaOH)

Mass of Beaker (Step 1; g)	Mass of Beaker + Citric Acid (Step 3; g)	Mass of Citric Acid (Step 1 - Step 3; g)	Mass of Beaker + Citric Acid After Cooling (Step 7; g)	Molarity of Citric Acid Solution (M)
108.7	110.7	2.00	110.74	0.104M

trial 1

30                                                                      00                                                                       13.1
29                                                                      1                                                                         12.5
28                                                                      2                                                                         12.1
26                                                                     4                                                                         11.57
24                                                                      6                                                                        11.01
22                                                                      8                                                                         10.6
18                                                                      12                                                                       10.02
16                                                                      1 4                                                                      9.87
14.3                                                                   15.7                                                                   9.5
13.9                                                                   16.1                                                                   9
13.5                                                                   16.5                                                                   8.2
13                                                                      17                                                                       7.8
12.5                                                                   17.5                                                                   7.6
12                                                                      18                                                                      7.5
11                                                                      19                                                                       7
10.5                                                                   19.5                                                                   6.8
10                                                                      20                                                                      6.55
9.5                                                                     20.5                                                                   6.2
8.5                                                                    21.5                                                                    5.59

trial 2

Trial 2 Data

Syringe reading (mL)	Citric Acid Added (mL)	pH
30	0.0	13.1
28	2	12.22
26	4	11.6
24	6	11
22	8	10.5
18	12	10
16	14	9.8
14.5	15.5	9.6
13.9	16.1	9.2
13.7	16.3	8.8
13.5	16.5	8.3
13	17	7.84
12.5	17.5	7.5
12	18	7.3
11	19	7.01
10.5	19.5	6.82
10	20	6.45
9.5	20.5	6.2

Answer 1

From both trials equivlance poitn is at 16 ml of Acetic acid

conc of acetic acid = 0.104 M

vol of NaOH = 15 ml

molarity of NaOH used = 0.111 M