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Empirical and Molecular Formulas, Back Titration Fun, and Gas Laws for Kids

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Hannah

01/04/2023

Chemistry

Amount of Substance (includes back titration)

Empirical and Molecular Formulas, Back Titration Fun, and Gas Laws for Kids

This document covers empirical formula calculations, back titrations, and gas laws in chemistry. It provides detailed explanations and examples for each topic, aimed at helping students understand these fundamental concepts.

Empirical formula calculations involve finding the simplest whole number ratio of atoms in a compound.

Back titrations are used to determine the concentration of an unknown solution indirectly.

• The ideal gas law (PV = nRT) is explained, along with its applications and conditions.

• Concepts like percentage yield, atom economy, and water of crystallization are also discussed.

• The document includes numerous examples and calculations to illustrate these chemical principles.

...

01/04/2023

288

moles = mass
mr
moles = vol. x conc.
moles vol.
24
m
mr
h
m
mr
n
K
56.5
с
8.7
12
m
mr
n
To find emperical formula
→ simplest whole number ra

View

Page 2: Back Titration Calculations

This page focuses on back titration step by step examples and calculations, a crucial technique in A Level Chemistry Amount of Substance analysis.

The page begins by explaining the concept of back titration, which is used when a substance doesn't react directly with a standard solution or when the end point is difficult to detect.

Definition: Back titration involves adding an excess of known concentration to a sample, then titrating the excess with another standard solution.

A detailed example is provided, involving the analysis of impure calcium carbonate (CaCO₃) using hydrochloric acid (HCl) and sodium hydroxide (NaOH).

Example: 50cm³ of 0.5M HCl is added to 1.39g of impure CaCO₃, diluted to 250cm³, and 25cm³ of this solution is titrated against 0.1M NaOH.

The page walks through the step-by-step calculation process, including:

  1. Calculating the initial moles of HCl
  2. Determining the moles of NaOH used in the titration
  3. Calculating the moles of excess HCl
  4. Finding the moles of HCl that reacted with CaCO₃
  5. Calculating the moles and mass of pure CaCO₃
  6. Determining the percentage purity of the CaCO₃ sample

Highlight: The key to successful back titration calculations is carefully tracking the moles of each substance at each step of the process.

The page concludes by emphasizing the similarity between percentage purity calculations and percentage yield calculations, reinforcing the interconnectedness of various A Level Chemistry Amount of Substance concepts.

Vocabulary: Percentage purity is calculated by dividing the mass of pure substance by the total mass of the sample and multiplying by 100.

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Chemistry

288

1 Apr 2023

2 pages

Empirical and Molecular Formulas, Back Titration Fun, and Gas Laws for Kids

user profile picture

Hannah

@hannah_studys1012

This document covers empirical formula calculations, back titrations, and gas laws in chemistry. It provides detailed explanations and examples for each topic, aimed at helping students understand these fundamental concepts.

Empirical formulacalculations involve finding the simplest whole number... Show more

moles = mass
mr
moles = vol. x conc.
moles vol.
24
m
mr
h
m
mr
n
K
56.5
с
8.7
12
m
mr
n
To find emperical formula
→ simplest whole number ra

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Join milions of students

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Page 2: Back Titration Calculations

This page focuses on back titration step by step examples and calculations, a crucial technique in A Level Chemistry Amount of Substance analysis.

The page begins by explaining the concept of back titration, which is used when a substance doesn't react directly with a standard solution or when the end point is difficult to detect.

Definition: Back titration involves adding an excess of known concentration to a sample, then titrating the excess with another standard solution.

A detailed example is provided, involving the analysis of impure calcium carbonate (CaCO₃) using hydrochloric acid (HCl) and sodium hydroxide (NaOH).

Example: 50cm³ of 0.5M HCl is added to 1.39g of impure CaCO₃, diluted to 250cm³, and 25cm³ of this solution is titrated against 0.1M NaOH.

The page walks through the step-by-step calculation process, including:

  1. Calculating the initial moles of HCl
  2. Determining the moles of NaOH used in the titration
  3. Calculating the moles of excess HCl
  4. Finding the moles of HCl that reacted with CaCO₃
  5. Calculating the moles and mass of pure CaCO₃
  6. Determining the percentage purity of the CaCO₃ sample

Highlight: The key to successful back titration calculations is carefully tracking the moles of each substance at each step of the process.

The page concludes by emphasizing the similarity between percentage purity calculations and percentage yield calculations, reinforcing the interconnectedness of various A Level Chemistry Amount of Substance concepts.

Vocabulary: Percentage purity is calculated by dividing the mass of pure substance by the total mass of the sample and multiplying by 100.

moles = mass
mr
moles = vol. x conc.
moles vol.
24
m
mr
h
m
mr
n
K
56.5
с
8.7
12
m
mr
n
To find emperical formula
→ simplest whole number ra

Sign up to see the contentIt's free!

Access to all documents

Improve your grades

Join milions of students

By signing up you accept Terms of Service and Privacy Policy

Page 1: Amount of Substance Calculations

This page covers fundamental A Level Chemistry Amount of Substance equations and calculations essential for understanding stoichiometry and chemical reactions.

The page begins by introducing key equations for calculating moles, including the relationship between moles, mass, and relative molecular mass (Mr). It also presents the equation for calculating moles using volume and concentration.

Definition: Moles represent the amount of substance and can be calculated using mass, volume, or concentration.

The page then delves into more complex calculations, including determining empirical formulas, which represent the simplest whole number ratio of atoms in a compound.

Example: For potassium carbonate (K₂CO₃), the empirical formula is determined by finding the ratio of moles of each element.

The concept of water of crystallization is introduced, using magnesium sulfate (MgSO₄·xH₂O) as an example. Students learn how to calculate the number of water molecules (x) in hydrated compounds.

Highlight: Understanding water of crystallization is crucial for accurately representing hydrated compounds in chemical formulas.

The page also covers calculations involving gases at room temperature and pressure (RTP), introducing the ideal gas law (PV = nRT) and its applications.

Vocabulary: RTP refers to standard conditions where temperature is 25°C (298K) and pressure is 101 kPa.

Finally, the page explains percentage yield and atom economy calculations, which are important for assessing the efficiency of chemical reactions.

Example: Percentage yield is calculated by dividing the actual amount of product by the theoretical amount and multiplying by 100.

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Stefan S

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This app is really great. There are so many study notes and help [...]. My problem subject is French, for example, and the app has so many options for help. Thanks to this app, I have improved my French. I would recommend it to anyone.

Samantha Klich

Android user

Wow, I am really amazed. I just tried the app because I've seen it advertised many times and was absolutely stunned. This app is THE HELP you want for school and above all, it offers so many things, such as workouts and fact sheets, which have been VERY helpful to me personally.

Anna

iOS user

Best app on earth! no words because it’s too good

Thomas R

iOS user

Just amazing. Let's me revise 10x better, this app is a quick 10/10. I highly recommend it to anyone. I can watch and search for notes. I can save them in the subject folder. I can revise it any time when I come back. If you haven't tried this app, you're really missing out.

Basil

Android user

This app has made me feel so much more confident in my exam prep, not only through boosting my own self confidence through the features that allow you to connect with others and feel less alone, but also through the way the app itself is centred around making you feel better. It is easy to navigate, fun to use, and helpful to anyone struggling in absolutely any way.

David K

iOS user

The app's just great! All I have to do is enter the topic in the search bar and I get the response real fast. I don't have to watch 10 YouTube videos to understand something, so I'm saving my time. Highly recommended!

Sudenaz Ocak

Android user

In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.

Greenlight Bonnie

Android user

very reliable app to help and grow your ideas of Maths, English and other related topics in your works. please use this app if your struggling in areas, this app is key for that. wish I'd of done a review before. and it's also free so don't worry about that.

Rohan U

Android user

I know a lot of apps use fake accounts to boost their reviews but this app deserves it all. Originally I was getting 4 in my English exams and this time I got a grade 7. I didn’t even know about this app three days until the exam and it has helped A LOT. Please actually trust me and use it as I’m sure you too will see developments.

Xander S

iOS user

THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE THE SCHOOLGPT. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH 😍😁😲🤑💗✨🎀😮

Elisha

iOS user

This apps acc the goat. I find revision so boring but this app makes it so easy to organize it all and then you can ask the freeeee ai to test yourself so good and you can easily upload your own stuff. highly recommend as someone taking mocks now

Paul T

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