Predicting and Measuring the Mass of a Reactant in Excess

Experiment 6E

Predicting and Measuring the Mass of a Reactant in Excess

Block: E

Date: January 27, 2016

Purpose

The purpose of this lab is to help us review writing and balancing an equation, applying principals of stoichiometry, predicting amount of zinc's excess and analyze experimental results to determine unexpected results.

Materials

Refer to Health Lab Experiment, Lab 6E, page 93

Procedures

Refer to Health Lab Experiment, Lab 6E, page 93-94

* We only used 25 ml of 1.5 M HCl instead of filling the buret with 1.5 M HCl

Data and Observations

Part 1

Mass of test tube – 19.445g

Mass of test tube and zinc – 21.000g

Initial reading of 1.50 M HCl – 25.00mL

Last reading of 1.50 M HCl – 38.45mL

Mass of test tube and zinc after decanting, washing, and drying - 20.251g

Observations of test tube containing Zn after addition of HCl

Produced gas

Turned white/cloudy and milky

Slow reaction turned faster

Little bubbles sizzle in the tube

Zn slowly turned grey

After the reaction turned clear

Reacted Zn turned dark grey

Unreacted Zn remain its irony color

Part 2

Mass of test tube and zinc – 20.251g

Results

The excess of zinc is different from different calculations by 0.2g. We’ve got 0.6g of Zn using stoichiometry calculations and on the other hand, we’ve got 0.806 g of Zn through the use of experimentally measurement.

Discussion