CHEM 1211K Lecture 2: Metric Equivalents and add/ sub and multi/divide Sig Figs

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erinelk711

12 Sep 2016

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3. 83 x 10^3 (when rounding, you must reduce as well) 0. 500 (here instead of taking away digits, you have to add in order to meet the amount of sf) Add and subtracting - the answer is limited to the number of decimal places as the number that has the fewest decimal places. Example: 0. 250 + 0. 250 = 0. 500: if you have 3 sf after the decimal than your answer has to have 3 sf after the decimal as well. Multiplication and division - the answer is limited to the number of significant figures as the digit with the fewest significant figures. 8. 24 x 10^3 1. 1 x 10^-4: exact numbers. Determine by counting and not by using a measure device. Assume to have an infinite number of sf. Examples: 1 inch = 2. 54 cm (exactly, 9 pencils (exactly : obtained by counting.

Part I: What is the complete formula (Salt · x H2O) for the hydrate you will be given in lab?

(25 points)

General Procedural guidelines for this lab:

From the very beginning of this experiment, only handle the crucible or evaporating dish with crucible tongs. SAFETY: The crucible will be very hot! Never touch the crucible while it could be hot. Use crucible tongs.
Use the same scale throughout this lab.
Do all of your calculations with proper sig figs.
For additions and subtractions, keep the fewest number of decimal places.
For multiplication and division keep the fewest number of significant figures.
While things are heating and cooling, work on Part II of this task.

Procedure: Watch this video, read along with the following procedure, and take notes: https://www.youtube.com/watch?v=k2s-YG15eIA

Wash out a crucible and flame dry. Heat the crucible with a Bunsen burner for 5 minutes on high and let it cool for 10 minutes.

Zero the balance.
Mass the crucible and record the mass (with units). __________

Fill the crucible about ¾ full with the hydrate.

Mass the crucible with the hydrate and record this mass. __________

Record the color of the hydrate (before heating). __________

Heat the crucible with the until all water is driven off. What is left in the crucible is the anhydrate.

Record the color of the anhydrate (after heating). __________

Let the crucible cool for a few minutes (at least 10). Then mass the anhydrate and crucible and

record this mass. __________

Complete the calculations to determine the (i) % mass of water in the hydrate and (ii) the value for x for your hydrate. Show all of your calculations. The calculations for the % mass of water in the hydrate are outlined in the video. You will have to do the calculations for x by yourself. Show all of your calculations on this page or another page.

MAKE A DATA TABLE HERE FOR ALL OF YOUR DATA:

MAKE A RESULTS TABLE HERE FOR THE RESULTS OF YOUR CALCULATIONS:

sapphiremouse524

Need help with part B and C

CHEM 1211K Lecture 2: Metric Equivalents and add/ sub and multi/divide Sig Figs

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Related Questions

Part I: What is the complete formula (Salt · x H2O) for the hydrate you will be given in lab?

(25 points)