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43 Cards in this Set
- Front
- Back
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What’s the definition of atom |
The smallest part of an element that has the properties of this element |
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Define element |
A substance made of only one type of atoms |
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Define ion |
A species made of one or more atoms joined having a positive or negative charge |
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Define molecule |
The simplest unit of a chemical compound that can exist, consisting of two or more atoms held together by chemical bonds |
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Define compound |
A Substance made up of two or more elements chemically bonded together |
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Define empirical formula |
The formula that tells us the simplest ratio of the different atoms present in a molecule |
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Define molecular formula |
The formula that tells us the actual numbers of each type of atoms in a molecule |
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Define Mole (n) |
The amount of that substance that has the same number of identical entities (atoms, molecules or ions) as there are atoms in exactly 12g of the carbon 12-isotope |
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Define molecular mass (M) |
The mass per mole of a substance in g/mol |
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Define Avogadro’s constant (L) |
The number of particles in a mole (6x10^23 of particles) |
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What happens when soluble ionic compounds are dissolved in water? |
The ions separate |
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Why do solids liquids and gases have no charge |
Because they are neutral |
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Why must we cancel out ions are common and post sides, what is this called? |
Because they do not take part in the equation they are called spectator ions |
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How do you calculate the percentage composition |
1. Find the molecular mass (Mr) of the entire compound 2. find the molar mass of each element in the compound 3. divide the molar mass of each element by the entire molecular mass and multiply by a 100 |
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What’s the formula to find out the moles of an element |
Moles = mass (percentage)/ atomic mass |
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What is atom economy? |
Atom economy is the proportion of reactant atoms that become part of the desired product |
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When does atom economy decrease |
The atom economy decreases when there are many waste products |
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When is atom economy at 100% |
The atom economy is 100% when there is only one product |
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What’s the atom economy formula |
Atom economy = (Mr of desired product/ Mr of all products)*100 |
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What can Advogadros number (6*10^23) be used for |
Advogadros number can be used to count the number of particles (atoms ions protons…) |
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How can you convert from moles to atoms |
Multiply the molar amount by Advogadros number (L) |
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What is the theoretical yield? |
theoretical yield is the maximum mass of a product that can be made if no mass was wasted (the actual yield is always less than the theoretical yield) |
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What is the %yield formula? |
%yield= (actual yield/theoretical yield)*100 |
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What is the concentration (C) of a solution? |
The concentration (C) of a solution is the number of solutes dissolved in a solvent (usually water) |
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What is the concentration? |
The concentration is the number of moles of solutes in the volume (dm^3) of the solvent |
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When are solutions more concentrated? |
Solutions are more concentrated when there are more moles (n) of solutes and less volume (V) of the solvent |
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What is parts per million (ppm) often used for? |
PPM is often used for gaseous pollutants in the air or soluble pollutants in water |
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What is ppm usually used for? |
The “parts” stands for the mass (in grams) of a substance in a million of a solvent |
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In the case of gases PPM can be also expressed in unit of volume __ |
Dm^3 |
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How do you convert a percentage to ppm |
X10^4 |
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How do you convert a percentage to ppm |
X10^4 |
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How do you convert ppm to a percentage |
Divide by 10^4 |
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How do you convert a percentage to ppm |
X10^4 |
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How do you convert ppm to a percentage |
Divide by 10^4 |
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What are the two formulas of ppm |
Ppm= (grams of solute/grams of solution)*10^6 & ppm=(volume of solute/volume of gas mixture)*10^6 |
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What is the molar volume |
The molar volume is the volume that is occupied by one mole of a gas which is equal to 24dm^3 (or 24000 cm^3) |
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What temperature and pressure must the molar volume value be used at |
The temperature 25°C or 289K and pressure 1.01×10^5 Pascals |
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What temperature and pressure must the molar volume value be used at |
The temperature 25°C or 289K and pressure 1.01×10^5 Pascals |
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When at the right temperature & volume how do we calculate the volume of any gas |
By multiplying it’s number of moles (n) by 24 |
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What does the volume of gas occupies depend on |
Pressure and temperature |
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What happens when a gas is heated at constant pressure |
The gas expands and its volume increases |
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What happens when a gas volume decreases at a constant temperature |
The gas molecules hits the wall of the container more often and the pressure increases |
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What is the volume of gas of gas proportional |
The volume of a gas is also proportional to its number the moles |
