Back to AI Flashcard MakerChemistry /Chemistry: 1.2 Amounts of Substance Part 2

Chemistry: 1.2 Amounts of Substance Part 2

Chemistry35 CardsCreated 2 months ago

This flashcard set introduces stoichiometry and volumetric analysis, explaining how balanced equations help determine mole ratios in reactions. It also outlines how titration techniques are used to calculate unknown concentrations using a standard solution.

what does stoichiometry tell you

the relative number of moles of reactant and products involved in a reaction

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Key Terms

Term
Definition

what does stoichiometry tell you

the relative number of moles of reactant and products involved in a reaction

what is stoichiometry found from

the balanced equation

what is volumetric analysis used for

to find the volume of one solution which is needed to react with a measured volume of another solution

what can the results of volumetric analysis be used to find

the unknown concentration of one of the solutions

what is the solution with the known concentration called

the standard solution

the 4 steps to making a standard solution:

dissolve known mass of solid in de-ionised water

using a funnel, transfer into a volume...

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TermDefinition

what does stoichiometry tell you

the relative number of moles of reactant and products involved in a reaction

what is stoichiometry found from

the balanced equation

what is volumetric analysis used for

to find the volume of one solution which is needed to react with a measured volume of another solution

what can the results of volumetric analysis be used to find

the unknown concentration of one of the solutions

what is the solution with the known concentration called

the standard solution

the 4 steps to making a standard solution:

dissolve known mass of solid in de-ionised water

using a funnel, transfer into a volumetric flask; include washings

make up to the graduated line by carefully adding de-ionised water, making sure the meniscus sits on the line

stopper the flask and invert to mix the contents thoroughly

how to find the concentration of a solution of base

fill a burette with a known concentration of the acid

pipette a known volume of base into a conical flask

add a few drops of indicator to the base in the flask

add the solution of the acid from the burette until the indicator just changes colour- known as end point

record volume of acid added to nearest 0.05cm cubed
perform a rough titration and then sufficient accurate ones until the titres are concordant (within 0.01cm cubed of eachother)

calculate the mean titre from concordant titres to 2 d.p.

what colour is methyl orange in acid

red

what colour is methyl orange in base

yellow

what is methyl orange’s end point colour

orange

what colour is phenolphthalein in acid

colourless

what colour is phenolphthalein in base

pink

what is phenolphthalein’s end point colour

colourless

What are acid base titration calculations used for

To find the concentration of a solution of the volume of solution which reacts

What is a hydrated salt

A salt which contains water

What happens when hydrated salts are heated

The water is driven off and the compound is said to be anhydrous


What does waters of crystallisation refer to

The water molecules which form an essential part of the crystalline structure of a hydrated salt


How to calculate the number of moles of water of crystallisation

  • you will need to know the masses of the hydrated and anhydrous salts

  • mass of water = mass of hydrated salt - mass anhydrous salt

  • work out the number of moles of anhydrous salt and of water

  • find the simplest whole number ratio

What is percentage yield

A measure of the success of a laboratory preparation

How to work out percentage yield

Actual yield of product/theoretical yield of product x 100

Do both values need to be in moles for the percentage yield formula

Yes

What is theoretical yield

The number of moles expected if the reactants were completely converted into products

How to work out theoretical yield

Calculating the number of moles of reactants used and then using the balanced equation to calculate the number of moles of product if the yield was 100%

What is actual yield

The actual number of moles of product formed in the reaction

What is atom economy

A measure of the efficiency of a reaction in terms of the atoms involved

What does atom economy consider

Desired product and by products

Atom economy equation

Mr of desired product/sum of Mrs of all products x 100

What can atom economy be calculated from

The balanced equation

What is atom economy's significance in terms of the environment

Lots of waste products

Addition reaction

Have an atom economy of 100%- one product made

Substitution and elimination reactions

Have an atom economy of less than 100%- at least 2 products made

What is sustainable chemistry

The design of chemical products and processes that reduce the use of hazardous substances and generation of waste

What does sustainability mean

Developing industrial processes that prevent the depletion of the earths natural resources

Rules for chemical sustainability

  1. Reduce use of hazardous chemicals

  2. Reduce amount of waste

  3. Recycle waste

  4. Use fewer chemicals

  5. Design for energy efficiency i.e. Use s catalyst and renewable energy resource

  6. Use renewable feedstocks

  7. Manufacture biodegradable products

  8. Think safety

  9. Establish international cooperation

What are the downsides of green chemistry

  1. Cost- research = people = £

  2. Reduction of land needed for food

  3. Adhering to international agreements