Flashcards
Amount of Substance
Flashcards do conjunto (36)
- 1What is amount of substance measured in?Moles (n)
- 2How many particles are in a mole?6.02 x 10²³ (the Avogadro constant)
- 3What is the equation for finding the number of moles, given the number of particles?
- 4What is the unit for molar mass?gmol⁻¹
- 5TRUE OR FALSE: Molar mass has the same numerical value as the relative molecular/formula massTRUE
- 6What is the equation linking number of moles to the mass of substance and molar mass?
- 7How do you find the number of moles, particles or atoms in a sample?Multiply the number of moles in a sample by Avogadro's constant
- 8Complete the sentences: If temperature and __________ stay the same, one mole of any gas always has the same _________ - this is known as the molar ______ __________ (dm³mol⁻¹). At room temperature and pressure (______k, _____kPa), the molar gas volume is ____ dm³mol⁻¹ (or __________ cm³mol⁻¹)If temperature and PRESSURE stay the same, one mole of any gas always has the same VOLUME - this is known as the molar GAS VOLUME (dm³mol⁻¹). At room temperature and pressure (298k, 100kPa), the molar gas volume is 24 dm³mol⁻¹ (or 24,000 cm³mol⁻¹)
- 9What is the equation linking number of moles and volume of a gas?
- 10What is the ideal gas equation?pV = nRT
p = pressure (Pa)
T = temperature (K)
n = moles
R = gas constant (JK⁻¹mol)
V = volume (m³) - 11What is the conversion between kPa and Pa?
- 12What is the conversion between °C and K?
- 13What is the conversion between cm³ and dm³?
- 14What is the conversion between cm³ and m³?
- 15What is the conversion between m³ and dm³?
- 16Complete the sentence: The concentration of a solution is how many ______ (or how many ______) of something are dissolved per 1dm³ of solution in moldm⁻³ (or ________).The concentration of a solution is how many MOLES (or how many GRAMS) of something are dissolved per 1dm³ of solution in moldm⁻³ (or gdm⁻³)
- 17What is the equation that links number of moles with concentration and volume?
- 18What is an empirical formula?The smallest whole number ratio of atoms of each element in a compound
- 19What is a molecular formula?The actual numbers of atoms of each type of element in a molecule
- 20How do you find the molecular formula given the empirical formula and molecular mass?1. Find empirical mass
2. Divide molecular mass by empirical mass
3. Multiply empirical formula by that number (step 2) - 21What are the two ways of calculating empirical formulas?From experimental data
From percentage composition - 22Outline how the empirical formula is calculated using experimental data1. Work out how many moles of each product has been made
2. Use moles of each product to work out how many moles of each atom you started with
3. Write down ratio of moles present at the start
4. Divide by the smallest number of moles to get a whole number ratio - 23What is meant by 'conservation of mass'?Mass of products = mass of reactants
- 24Outline how the empirical formula is calculated using percentage compositions1. Divide percentages by molecular mass
2. Divide by the smallest number of moles to get a whole number ratio - 25Complete the sentences: The water in a lattice is called ________ _____ _____________. A solid salt containing water of crystallisation is ___________. A salt is ______________ if it doesn't contain water of crystallisation.The water in a lattice is called WATER OF CRYSTALLISATION. A solid salt containing water of crystallisation is HYDRATED. A salt is ANHYDROUS if it doesn't contain water of crystallisation.
- 26Outline the method for finding the formula of hydrated salts from experimental data1. Find mass of water lost by taking the mass of anhydrous salt away from mass of hydrated salt
2. Find number of moles of water lost
3. Work out mole ratios of anhydrous salt : moles of water
4. Scale up/down so the ratio is 1:n - 27What is theoretical yield?The theoretical yield is the mass of product that should be formed in a chemical reaction
- 28What is the assumption made with theoretical yield?No chemicals are 'lost'
- 29The actual mass/yield will always be less than the theoretical yield. Why?Not all chemicals react fully
Some chemicals are 'lost' (between transfers) - 30What is the equation for percentage yield?
- 31What is atom economy?A measure of the proportion of reactant atoms that become part of the desired product in the balanced chemical equation
- 32What is the equation for atom economy?
- 33TRUE OR FALSE: In addition reactions, the atom economy is always 100%TRUE
The reactants combine to form a single product so no atoms are wasted - 34TRUE OR FALSE: In substitution reactions, atom economy can sometimes be 100%FALSE
A substitution reaction results in more than one product being formed so the atom economy is always LESS THAN 100% - 35In industry, why are low atom economies bad?Less sustainable
Lots of waste product (costs money to separate desired from waste, and also to dispose of waste safely)
Reactants are expensive - 36In industry, what could be done to waste products (apart from disposal)?Sold
Used for something else
Informações
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- O usuário eliminou as informações de disciplina FlashCards sobre Amount of Substance, criado por Usuário eliminado em 05-03-2018.
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- Usuário eliminado · mar 2018
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- 5 mar 2018
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- Criado por Yinka F · 19 fev 2018
- Copiado por Yinka F · 5 mar 2018
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