Hey gang! Another new lab! In this lab, we will be investigating (you guessed it) acids, bases, and energy. You will be working with concentrated bases and acid solutions - these are as dangerous as things get in here! You MUST use goggles or your lab privileges will be suspended for the remainder of the lab session, and an appointment will be made for you to make up the time after school. THIS IS YOUR WARNING!
One definition of an acid is any substance that forms H+ ions when placed
in aqueous solution. A similar definition of a base is any substance
that produces OH- when placed in aqueous solution. An acid and a
base mixed are said to neutralize each other, and produce water and a salt.
See the first titration lab for memory refreshment.
Concentrated hydrochloric acid will cause severe burns on the skin, and its vapors will cause damage to your nasal mucous membranes. It must be used under the hood.
Sodium hydroxide comes in small white pellets that will also burn the skin. DO NOT touch them - use a spatula and gloves. Sodium hydroxide also absorbs quite a bit of water from the atmosphere, so as soon as you have obtained pellets from the container, cap it tightly (even if someone is waiting for it). Students observed walking away from an uncapped bottle of sodium hydroxide will be penalized when the lab is graded.
Part 1 Heat of Solution
Part 2 Heat of Neutralization
Part 3 A Penny Wasted...
Part 4 Clean-Up
Show all the work for any of these that have calculations involved.
1. Concentration of stock HCl __________
V of concentrated HCl to make 50.0 mL of 2.0 M solution. __________ mL
V of water
needed to make 50.0 mL of 2.0 M solution. __________ mL
2. What does the flask feel like?
3. Necessary mass of NaOH to make
100 mL of 1.0 M solution. __________ g
the outside of the flask feel like?
4. Acid + blue pH paper:
Base + blue pH paper:
5. Acid + red pH paper:
Base + red pH paper:
6. Starting T of acid solution __________ °C
Starting T of base solution __________ °C
7. Maximum temperature reached (of mixture) __________ °C
8. Final mixed solution + blue pH paper:
9. Final mixed solution + red pH paper:
10. [What does it taste like?]
Specific Heat of water __________ cal/gC°
11. Energy gained by 50.0 mL of acid solution
gained by 50.0 mL of base solution __________ cal
gained by both solutions __________ cal
equation for sodium hydroxide reacting with HCl
HCl used (see #1) __________ mol
NaOH used (see #3) __________ mol
water formed __________ mol
of Neutralization of HCl __________ kcal/mol
12. Penny + four drops of nitric acid.
What do you see?
13. Cover the dish with a watch glass.
What do you see?
17. What will you buy with your share of the
[Heat of Neutralization score sheet][MHS Chem page]