CHEM 053
SBE & Experiment 1
CHEM 053
Determining an Empirical Formula
Today’s Agenda: • • • •
CHEM 053
Review announcements Discuss safety and lab accidents SBE: Mass and Volume Measurement EF: Determining an EF
• Things that are DUE: • BEFORE TOMORROW: safety agreement & safety quiz • IN LAB: SBE questions (done in Notebook), EF notebook pages (data collections) • NEXT WEEK: EF Data Sheet
Where are we going?
CHEM 053
UNIT 1: Understanding Substances & Reactions UNIT 2: Analyzing Elements & Substances UNIT 3: Investigating Reactions We will now begin learning lab techniques and doing experiments to understand chemical substances
Course Material
CHEM 053
All you need to know about the structure of this Chemistry Lab is posted online.
Link to Blackboard: https://courseweb.library.upenn.edu
Let’s review the most important points!
What do you need?
CHEM 053
§ Yourself -‐ Participation MANDATORY § Calculator and/or laptop computer § Lab Notebook § Your Penn ID
Lab Notebooks
CHEM 053
What are some of the guidelines for keeping a lab notebook? • Pre-‐write tables, etc. • Leave a lot of space • ? • ?
LAB SAFETY !?!
CHEM 053
We expect everyone to LEARN and FOLLOW safe lab practices! We will take a few minutes now to review some basic safety information. You can always consult the safety section on Blackboard, your instructor, or TA for more information.
What to do if…
CHEM 053
You spill acid on the bench? You spill acid on your arm? You get a chemical in your eye? You break a piece of glassware?
In Lab This Week!
CHEM 053
Skill Building Exercise & Empirical Formula You MUST attend lab on time! Let’s review the experiments:
SBE! Transferring and Measuring chemicals Using a Balance
CHEM 053
Mass & Volume Measurement!
CHEM 053
Comparing Vol. pipet and graduate cylinder! Using a graduated pipet! Using transfer pipet!
SBE! Using a Balance
CHEM 053
Lab Etiquette
CHEM 053
Recap ALL Bottles at hood and balance bench. Clean up after yourself.
CHEM 053
This Week! Experiment 1
Determining an Empirical Formula Using a Balance Becoming familiar with the lab Keeping a notebook
Textbook Readings
CHEM 053
§ 3.1 & 3.2 Atomic Masses and the Mole § 3.4
Percent Composition
§ 3.5
Determining Formulas
(Review NAMING in Chapter 2 if you are not comfortable with naming ions and compounds) MEMORIZE Table 2.5!
CHEM 053 Molecular or Covalent Compounds Substances in which “particles” are composed of two or more DIFFERENT ATOMS joined together are called compounds.
H2 O
Molecule
Molecular Formula
Symbolic
Compound
Pure substance
Macroscopic
All “particles” are identical
(Water)
Microscopic
CHEM 053
How do we know how many atoms of each type?
We perform elemental analysis of the compound Find the percentage of each element present in the substance and use it to find relative proportions. During physical activity, a substance forms in muscle tissue and is responsible for muscle soreness. 40.0% C, 6.71% H, 53.3% O Always the same proportions à Chemical Compound
Counting Particles
CHEM 053
Is it practical, in a lab situation, to physically COUNT the particles? NO!! The particles are too small! So – how do we typically measure the amount of a substance we have in a laboratory? We use the MASS to determine the amount of substance. How is mass related to the number of particles?
Molar Mass
CHEM 053
The mass of one mole of atoms is called the Molar Mass of the element Average Mass (g) = Molar Mass The Molar Mass is the mass of 6.0221 x 1023 of particles of a given substance. 1 mol of C = 6.0221 x 1023 atoms of C M(C) = 12.0107 g/mol
How do they compare?
CHEM 053
6.0221 x 1023 particles or units in each If we weigh them, the mass we get is called the “Molar Mass”
These are one mole of 6 different substances.
In Lab This Week…
CHEM 053
You can complete the data sheet and turn it in before you leave.
A few more reminders…
CHEM 053
§ Next time, remember to bring: § Your lab notebook § A lock for the locker in the hall § Your drawer key § Your Penn ID § Wear appropriate clothes and bring your safety glasses and apron. § Sign the safety agreement online and take the safety quiz on Bb
Questions?
CHEM 053
Your TA and I are here to help. Check Blackboard FREQUENTLY.
Email with any questions!
CHEM 053
Determining an Empirical Formula
Today’s Agenda: • • • •
CHEM 053
Review announcements Discuss safety and lab accidents SBE: Mass and Volume Measurement EF: Determining an EF
• Things that are DUE: • BEFORE TOMORROW: safety agreement & safety quiz • IN LAB: SBE questions (done in Notebook), EF notebook pages (data collections) • NEXT WEEK: EF Data Sheet
Where are we going?
CHEM 053
UNIT 1: Understanding Substances & Reactions UNIT 2: Analyzing Elements & Substances UNIT 3: Investigating Reactions We will now begin learning lab techniques and doing experiments to understand chemical substances
Course Material
CHEM 053
All you need to know about the structure of this Chemistry Lab is posted online.
Link to Blackboard: https://courseweb.library.upenn.edu
Let’s review the most important points!
What do you need?
CHEM 053
§ Yourself -‐ Participation MANDATORY § Calculator and/or laptop computer § Lab Notebook § Your Penn ID
Lab Notebooks
CHEM 053
What are some of the guidelines for keeping a lab notebook? • Pre-‐write tables, etc. • Leave a lot of space • ? • ?
LAB SAFETY !?!
CHEM 053
We expect everyone to LEARN and FOLLOW safe lab practices! We will take a few minutes now to review some basic safety information. You can always consult the safety section on Blackboard, your instructor, or TA for more information.
What to do if…
CHEM 053
You spill acid on the bench? You spill acid on your arm? You get a chemical in your eye? You break a piece of glassware?
In Lab This Week!
CHEM 053
Skill Building Exercise & Empirical Formula You MUST attend lab on time! Let’s review the experiments:
SBE! Transferring and Measuring chemicals Using a Balance
CHEM 053
Mass & Volume Measurement!
CHEM 053
Comparing Vol. pipet and graduate cylinder! Using a graduated pipet! Using transfer pipet!
SBE! Using a Balance
CHEM 053
Lab Etiquette
CHEM 053
Recap ALL Bottles at hood and balance bench. Clean up after yourself.
CHEM 053
This Week! Experiment 1
Determining an Empirical Formula Using a Balance Becoming familiar with the lab Keeping a notebook
Textbook Readings
CHEM 053
§ 3.1 & 3.2 Atomic Masses and the Mole § 3.4
Percent Composition
§ 3.5
Determining Formulas
(Review NAMING in Chapter 2 if you are not comfortable with naming ions and compounds) MEMORIZE Table 2.5!
CHEM 053 Molecular or Covalent Compounds Substances in which “particles” are composed of two or more DIFFERENT ATOMS joined together are called compounds.
H2 O
Molecule
Molecular Formula
Symbolic
Compound
Pure substance
Macroscopic
All “particles” are identical
(Water)
Microscopic
CHEM 053
How do we know how many atoms of each type?
We perform elemental analysis of the compound Find the percentage of each element present in the substance and use it to find relative proportions. During physical activity, a substance forms in muscle tissue and is responsible for muscle soreness. 40.0% C, 6.71% H, 53.3% O Always the same proportions à Chemical Compound
Counting Particles
CHEM 053
Is it practical, in a lab situation, to physically COUNT the particles? NO!! The particles are too small! So – how do we typically measure the amount of a substance we have in a laboratory? We use the MASS to determine the amount of substance. How is mass related to the number of particles?
Molar Mass
CHEM 053
The mass of one mole of atoms is called the Molar Mass of the element Average Mass (g) = Molar Mass The Molar Mass is the mass of 6.0221 x 1023 of particles of a given substance. 1 mol of C = 6.0221 x 1023 atoms of C M(C) = 12.0107 g/mol
How do they compare?
CHEM 053
6.0221 x 1023 particles or units in each If we weigh them, the mass we get is called the “Molar Mass”
These are one mole of 6 different substances.
In Lab This Week…
CHEM 053
You can complete the data sheet and turn it in before you leave.
A few more reminders…
CHEM 053
§ Next time, remember to bring: § Your lab notebook § A lock for the locker in the hall § Your drawer key § Your Penn ID § Wear appropriate clothes and bring your safety glasses and apron. § Sign the safety agreement online and take the safety quiz on Bb
Questions?
CHEM 053
Your TA and I are here to help. Check Blackboard FREQUENTLY.
Email with any questions!
