C1 Flash Cards From Fsl
In an element, all of the atoms are _______
the same
What happens when atoms of magnesium and atoms of sulfur are chemically combined?
They form a compound.
This process involves a chemical reaction where the elements combine to create a new substance.
What do compounds contain?
Two or more different elements chemically combine in a fixed proportions
Compounds are distinct from mixtures, which can vary in composition.
What is a mixture?
A combination of different elements or compounds that are not chemically combined
Mixtures can be homogeneous or heterogeneous.
Are the components of a mixture chemically combined?
No, they are not chemically combined
This differentiates mixtures from compounds.
What do you have to use to separate a compound
A chemical reaction
What is a method to separate a mixture without a chemical reaction?
Physical separation technique
Name a physical separation technique that can be used to separate mixtures.
Filtration, distillation, crystallisation, or chromatography
Each method serves a specific purpose depending on the properties of the components in the mixture.
Fill in the blank: We can use _______ to separate a mixture rather than a chemical reaction.
physical separation technique
True or False: Distillation is a chemical reaction used to separate mixtures.
False
What is the purpose of using filtration in separation techniques?
To separate solids from liquids
What does crystallisation achieve in the context of mixture separation?
It separates solids from solutions based on solubility differences
What is chromatography used for?
To separate components of a mixture based on their movement through a medium
What is the difference between a compound and a molecule?
A compound has different elements chemically combined, while a molecule can have any elements chemically combined, even if they are the same element.
What are examples of compounds?
Examples of compounds include:
* Water (H2O)
* Ammonia (NH3)
* Methane (CH4)
What elements does methane contain?
Methane contains the elements carbon and hydrogen.
What elements does water contain?
Water contains the elements hydrogen and oxygen.
What elements does ammonia contain?
Ammonia contains the elements nitrogen and hydrogen.
True or False: Chlorine and oxygen are compounds.
False
What is the composition of a chlorine molecule?
A chlorine molecule contains two chlorine atoms chemically combined.
What is the composition of an oxygen molecule?
An oxygen molecule contains two oxygen atoms chemically combined.
Fill in the blank: All compounds are ______, but not all molecules are compounds.
molecules
What can physical separation techniques be used for?
To separate mixtures
Physical separation techniques cannot be used to separate elements in a compound.
What cannot be separated using physical separation techniques?
Elements in a compound
Physical separation techniques are ineffective for compounds.
How can elements in a compound be separated?
By chemical reaction such as reduction or by electrolysis
These methods involve changing the chemical structure of the compound.
Fill in the blank: Physical separation techniques can only be used to separate _______.
mixtures
True or False: Physical separation techniques can separate elements in a compound.
False
What is the purpose of filtration?
To separate an insoluble solid from a liquid
What does the term ‘insoluble’ mean?
The solid will not dissolve in the liquid
What are state symbols?
Symbols that indicate the physical state of a chemical
What does the state symbol ‘S’ represent?
Solid
What does the state symbol ‘L’ represent?
Liquid
Is silver chloride soluble in water?
No, silver chloride is insoluble in water
Fill in the blank: Silver chloride is a _______ in water.
solid
True or False: The state symbol for water is ‘S’.
False
What is a solid material suspended in a liquid that cannot be seen individually?
Silver chloride
Silver chloride is used as an example to illustrate the concept of suspension in this context.
What technique can be used to separate an insoluble solid from a liquid?
Filtration
Filtration is a common physical separation technique in chemistry.
What apparatus is used in the process of filtration?
Filter funnel and filter paper
These tools are essential for conducting the filtration process.
What happens to the liquid during filtration?
It passes through the filter paper and is called the filtrate
The filtrate is the liquid that has been separated from the solid.
What happens to the solid material during filtration?
It is trapped at the end of the filter paper
In this case, the solid material is silver chloride.
Fill in the blank: Filtration separates an _______ solid from a liquid.
insoluble
Insoluble solids do not dissolve in the liquid, making them suitable for filtration.
True or False: The filtrate is the solid material left on the filter paper.
False
The filtrate refers to the liquid that has passed through the filter, not the solid.
What is the outcome of the filtration process?
A liquid separated from a solid
The process effectively separates two distinct phases in a mixture.
What is crystallisation used for?
To separate a soluble solid from a liquid
What happens when sodium chloride is mixed with water?
Sodium chloride dissolves to form a sodium chloride solution (aq)
What does the symbol (aq) indicate?
That sodium chloride is dissolved in water
What occurs when a sodium chloride solution is left for a few days?
The water evaporates, leaving solid sodium chloride
What state symbol is used for solid sodium chloride?
S
How can crystallisation be made faster?
By gently heating the solution to evaporate the water
What is a caution when heating certain chemicals?
They may break down if heated
Fill in the blank: The water evaporating from sodium chloride solution leaves behind _______.
solid sodium chloride
True or False: Sodium chloride remains in solution after evaporation of water.
False
What is the main purpose of simple distillation?
To separate a dissolved solid from a liquid while keeping the liquid
What are the two stages of simple distillation?
- Evaporation of the liquid by heating
- Condensation of the vapour back to a liquid by cooling
What equipment is used to carry out simple distillation?
- Flask
- Continuous glass tube
- Condenser
- Thermometer
How is the condenser kept cold during simple distillation?
By circulating cold water from the tap through the condenser
What happens to the thermometer reading during simple distillation?
The thermometer reading increases as the vapour passes over it
What happens to the vapour as it passes through the condenser?
It condenses back into a liquid
What is collected in the beaker at the end of simple distillation?
The liquid that has been condensed
What is left in the flask after simple distillation?
Crystals of the solid
Can simple distillation be used to produce drinking water from seawater?
Yes, but it requires a great deal of energy
True or False: Simple distillation is the most common method used to produce drinking water.
False
Fill in the blank: Simple distillation consists of _______ and _______.
[evaporation], [condensation]
What is the purpose of fraction distillation?
To separate a mixture of liquids with different boiling points.
What is the key difference between fraction distillation and simple distillation?
Fraction distillation uses a fractionating column.
What is the function of the fractionating column in fraction distillation?
It allows repeated evaporation and condensation of vapors to increase the purity of the lower boiling point liquid.
What components are found at the top of the fractionating column?
A thermometer and a condenser.
In the example given, what are the boiling points of the two liquids being separated?
80°C and 100°C.
What happens when the mixture of liquids is heated in fraction distillation?
Both liquids start to evaporate, with the one having the lower boiling point evaporating more easily.
What indicates that a mixture of vapors is passing over the thermometer?
The temperature on the thermometer begins to rise.
At what point does the temperature on the thermometer stop rising during fraction distillation?
When the lower boiling point liquid is mainly passing into the condenser.
Fill in the blank: The first proper fraction is collected when the thermometer indicates _______.
80°C.
What happens after collecting the first fraction at 80°C?
The temperature on the thermometer begins to rise again, indicating the collection of the second chemical.
What is a limitation of the equipment used in fraction distillation?
It is not useful for separating a very large volume of liquid.
True or False: If the two liquids have very similar boiling points, it is easier to separate them using fraction distillation.
False.
List the steps involved in fraction distillation.
- Gently heat the mixture
- Allow vapors to rise into the fractionating column
- Condense vapors in the condenser
- Collect fractions in beakers.
What technique used by scientists is called chromatography?
Chromatography
Chromatography is a physical separation technique that does not involve chemical reactions.
What is the main purpose of paper chromatography?
To separate substances based on different solubilities
This allows one to determine which colors are single or mixtures in ink.
What do we call the paper in paper chromatography?
The stationary phase
The stationary phase does not move during the chromatography process.
What do we call the liquid that dissolves substances in chromatography?
The mobile phase
The mobile phase moves up the paper and carries the dissolved substances with it.
What happens to a pure compound in chromatography?
Produces a single spot
This indicates that it is a single pure color.
What happens to a mixture in chromatography?
May separate into different spots
The number of spots indicates the number of different components in the mixture.
What is the significance of solubility in chromatography?
More soluble substances are more attracted to the mobile phase
This means they travel further up the paper than less soluble substances.
True or False: The position of the spot in chromatography changes with different solvents.
True
However, a pure substance will still produce a single spot regardless of the solvent used.
Why do we draw the starting line in pencil in chromatography?
To prevent the line from dissolving in the solvent
Using pen could cause the ink to move up the paper during the separation process.
Fill in the blank: A _______ is a liquid that will dissolve substances.
solvent
Different solvents can affect the separation process in chromatography.
What did ancient Greeks believe about atoms?
Everything is made of atoms
What did scientists discover in 1897 about atoms?
Atoms contain tiny negative particles called electrons
What was the plum pudding model?
An atom is a ball of positive charge with negative electrons embedded in it
What experiment was conducted to test the plum pudding model?
The Alpha experiment
What was the significance of the Alpha scattering experiment?
It changed the way that we think about atoms
What material was used in the Alpha scattering experiment and why?
Gold foil, because it can be hammered into very thin sheets
What are alpha particles?
Tiny particles fired at the gold foil in the Alpha experiment
What did scientists observe about most alpha particles in the experiment?
Most passed straight through the foil without changing direction
What does it indicate if alpha particles are deflected?
The center of the atom must have a positive charge
What conclusion can be drawn when alpha particles bounce straight back?
The center of an atom must contain a great deal of mass
What model replaced the plum pudding model?
The nuclear model
Describe the nuclear model of the atom.
Most of the atom is empty space, with a tiny positive nucleus containing most of the mass and negative electrons around the edge
Fill in the blank: The center of the atom is called the _______.
nucleus
True or False: The plum pudding model suggested that atoms have no internal structure.
False
What are isotopes?
Atoms of the same element with different numbers of neutrons.
What is the atomic number of both isotopes of chlorine?
17
How many neutrons does the chlorine isotope with a mass number of 35 have?
18 neutrons
How many neutrons does the chlorine isotope with a mass number of 37 have?
20 neutrons
What is the mass number for chlorine on the periodic table?
35.5
What is the method used to calculate the relative atomic mass of an element?
Weighted-average based on the abundance of each isotope.
What does the term ‘abundance’ refer to in the context of isotopes?
How common each isotope is.
How much more abundant is the chlorine isotope with a mass number of 35 compared to the one with a mass number of 37?
Three times more abundant
What is the significance of the relative atomic mass of chlorine being closer to 35 than to 37?
It reflects the greater abundance of the isotope with mass number 35.
Fill in the blank: The equation for calculating atomic mass is the mass number of isotope one multiplied by the percent abundance of isotope one added to the mass number of isotope two multiplied by the _______ of isotope two, all divided by 100.
abundance
True or False: The relative atomic mass is simply the average of the mass numbers of all isotopes.
False
What is the mass number of the chlorine isotope that is less abundant?
37
What is the atomic mass equation for an element based on its isotopes?
Mass number of isotope one * percent abundance of isotope one + mass number of isotope two * percent abundance of isotope two / 100
What is the maximum number of electrons that the first energy level can hold?
2 electrons
The first energy level is the closest to the nucleus and can hold a maximum of two electrons.
What is the maximum number of electrons that the second energy level can hold?
8 electrons
The second energy level can accommodate more electrons than the first.
What is the maximum number of electrons that the third energy level can hold?
8 electrons
The third energy level also has a maximum capacity of eight electrons before filling the next level.
How do we represent the number of electrons in the first energy level for hydrogen?
1 in the first energy level
Hydrogen has one electron, which is placed in the first energy level.
How do we represent the number of electrons in helium?
2 in the first energy level
Helium has two electrons, both of which occupy the first energy level.
How many electrons does lithium have?
3 electrons
Lithium consists of two electrons in the first energy level and one in the second.
In the case of lithium, how are the electrons distributed across the energy levels?
2 in the first, 1 in the second
The first energy level is not full for lithium.
What does the number of electrons in the outer energy level indicate?
The group number of that element
The outer energy level’s electron count corresponds to the group number in the periodic table.
What group is lithium in based on its outer energy level electron count?
Group 1
Lithium has one electron in its outer energy level.
How many electrons does beryllium have in the first energy level?
2 electrons
Beryllium has two electrons in the first energy level and two in the second.
How many electrons does beryllium have in the second energy level?
2 electrons
Beryllium’s configuration includes two electrons in both the first and second energy levels.
What is the periodic table?
A range of columns called groups that organizes elements with similar properties at regular intervals.
What does the term ‘periodic’ mean?
Occurs at regular intervals.
What are the elements in group one of the periodic table?
- Lithium
- Sodium
- Potassium
What type of elements are found in group seven of the periodic table?
Highly reactive nonmetals such as fluorine and chlorine.
Why do elements in the same group have similar chemical properties?
They have the same number of electrons in the outer energy level.
Who was Johann Dober and what did he observe?
A scientist who noticed that elements with similar chemical properties often occur in groups.
What is an example of elements that react similarly with water?
- Lithium
- Sodium
- Potassium
What is the law of octaves and who proposed it?
A concept by John Newlands that stated every eighth element reacts in a similar way.
What problem did Newlands’ law of octaves face?
Elements were sometimes grouped together despite having different properties.
Who developed the first modern periodic table?
Dmitri Mendeleev.
How did Mendeleev arrange the elements in his periodic table?
In order of increasing atomic weight.
What unique approach did Mendeleev take with his periodic table?
He switched the order of specific elements to fit patterns and left gaps for undiscovered elements.
What did Mendeleev predict about the missing elements?
He predicted their properties based on other elements in the same groups.
What is a significant difference between Mendeleev’s table and the modern periodic table?
The modern periodic table arranges elements by atomic number instead of atomic weight.
What issue arises from ordering elements by atomic weight?
Elements can appear in the wrong order due to isotopes.
What are the noble gases and when were they discovered?
Group 0 elements that had not been fully discovered when Mendeleev published his table.
What are the characteristics of noble gases?
Noble gases are very unreactive elements due to having a full outer energy level.
This stability prevents noble gases from reacting with other elements.
How many electrons does a helium atom have?
Helium has two electrons.
These electrons are located in the first energy level.
What is the maximum number of electrons that the first energy level can hold?
The first energy level can hold a maximum of two electrons.
Why are helium atoms stable?
Helium atoms are stable because their first energy level is full.
A full energy level corresponds to stability in atomic structure.
How many electrons does a neon atom have?
Neon has ten electrons.
Neon has two electrons in the first energy level and eight in the second.
What is the maximum number of electrons that the second energy level can hold?
The second energy level can hold a maximum of eight electrons.
Why is neon considered unreactive?
Neon is unreactive because its outer energy level is full.
How many electrons does an argon atom have?
Argon has eighteen electrons.
Argon has eight electrons in its outer energy level, making it stable.
What is the relationship between the boiling points of noble gases and their relative atomic mass?
The boiling points of noble gases increase as relative atomic mass increases.
Which noble gas has the lowest boiling point?
Helium has the lowest boiling point.
This is due to its low relative atomic mass of four.
Which noble gas has the highest boiling point?
Radon has the highest boiling point.
It has a relative atomic mass of 222.
Fill in the blank: All noble gases have boiling points lower than _______.
room temperature.
True or False: All noble gases are reactive due to their atomic structure.
False.
Noble gases are unreactive due to having full outer energy levels.
What are the two broad categories of metals in the periodic table?
Highly reactive metals and transition metals
Highly reactive metals are found in groups one and two, while transition metals are located in the center of the periodic table.
Where are metals located on the periodic table?
On the left and center
Nonmetals are found on the right side of the periodic table.
What happens when metals react?
They lose electrons to achieve a full outer energy level
This process gives them a stable electronic structure like that of a group 0 noble gas.
Which group do lithium and sodium belong to?
Group one
Both elements have one electron in their outer energy level.
What is the electronic structure of lithium after it loses an electron?
It becomes the same as helium
Lithium has three protons and three electrons, losing one electron gives it a full energy level like helium.
What is the electronic structure of sodium after it loses an electron?
It becomes the same as neon
Sodium has 11 protons and 11 electrons, losing one electron gives it a full energy level like neon.
What happens to aluminium when it reacts?
It loses three electrons
Aluminium is in group 3 and has three electrons in its outer energy level.
What is the overall charge of a neutral lithium atom?
Zero
A lithium atom has three protons and three electrons, resulting in no net charge.
What is the overall charge of a lithium ion after losing an electron?
One positive
After losing one electron, lithium has three protons and only two electrons.
How is a lithium ion represented?
With square brackets and the overall charge in the top right corner
This notation indicates that lithium has formed a positive ion.
What type of ions do metals always form?
Positive ions
This is a key characteristic of metal behavior during chemical reactions.
What is the group name for the metals that have one electron in the outer energy level?
Alkaline metals
How do group one metals react with oxygen?
They react rapidly with oxygen in the air
What compound is formed when lithium reacts with oxygen?
Lithium oxide
Which group one metal reacts more rapidly with oxygen, sodium or lithium?
Sodium
What compound is formed when sodium reacts with oxygen?
Sodium oxide
Which group one metal reacts even more rapidly than sodium and lithium?
Potassium
What compound is formed when potassium reacts with oxygen?
Potassium oxide
As we move down group one, how does the reactivity of the metals change?
The metals react more rapidly
How many outer electrons do lithium atoms have?
One
How many outer electrons do oxygen atoms have?
Six
What happens to the electron from the lithium atom when it reacts with oxygen?
It moves to the oxygen atom
What is the charge of a lithium ion after it reacts with oxygen?
Positive one charge
What is the charge of an oxide ion after the reaction?
Negative two charge
What is the result for the outer energy levels of lithium and oxygen after their reaction?
Both have a full outer energy level
Fill in the blank: The reaction between lithium and oxygen can be written as a chemical _______.
Equation
What are the physical properties of metals?
Metals are strong, malleable, excellent conductors of heat and electricity, and have high boiling and melting points.
Metals can be bent or hammered into different shapes, which is known as malleability.
What are the physical properties of non-metals?
Non-metals tend to be dull looking, brittle, not always solid at room temperature, do not usually conduct electricity, and often have a lower density.
Brittle means they break more easily when bent.
True or False: All metals have the same physical properties.
True.
Metals exhibit similar characteristics such as strength and conductivity.
Fill in the blank: Metals are great at conducting _______.
heat and electricity.
This property makes metals useful in electrical wiring and heating elements.
Fill in the blank: Non-metals tend to be ______ looking.
dull.
This contrasts with the shiny appearance often associated with metals.
What happens to non-metals when you try to bend them?
They break more easily because they are brittle.
This is different from metals, which can be bent without breaking.
Do non-metals usually conduct electricity?
No.
This is a key difference between metals and non-metals.
What is a common characteristic of metals regarding their state at room temperature?
Metals are usually solid at room temperature.
Mercury is an exception as it is a liquid metal.
Fill in the blank: Non-metals often have a ______ density.
lower.
This can affect their physical behavior and applications.
