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IB Chemistry videos / S1.1.1 Elements, Compounds and Mixtures Free video lesson IB · Chemistry
Chemistry S1.1.1a Learn Chemistry S1.1.1a in this free IB Chemistry video lesson for S1.1.1 Elements, Compounds and Mixtures.
About this video Learn Chemistry S1.1.1a in this free IB Chemistry video lesson for S1.1.1 Elements, Compounds and Mixtures.
Summary of the Video
This video explores the classification of matter into elements, compounds, and mixtures, as well as methods for separating mixtures. It begins by defining matter as anything with mass and volume, dividing it into pure substances (elements and compounds) and mixtures (homogeneous and heterogeneous).
Key Points:
Elements :
Found on the periodic table, arranged by atomic number.
Composed of only one type of atom and cannot be chemically broken down.
Examples: Hydrogen (H), Oxygen (O).
Compounds :
Formed by chemically combining two or more elements in fixed ratios.
Examples include:
Water: H 2 O H_2O H 2 O
Ethanol: C 2 H 5 O H C_2H_5OH C
Video transcript 00:00 In this video we'll be
00:02 looking at structure 1 .1
00:03 .1, which is elements, compounds
00:06 and mixtures, and we'll also
00:08 look at some separation techniques
00:10 such as evaporation, distillation and
00:13 chromatography. So we'll start by
00:17 looking at matter, which is
00:18 anything that has mass and
00:20 volume. So matter can be
00:23 divided into two categories. We
00:25 have pure substances,
00:28 and we have mixtures. And
00:31 then we can further divide
2
H 5
O
H
Sodium chloride: N a C l NaCl N a C l
Compounds have properties distinct from their constituent elements.
Mixtures :
Contain multiple elements or compounds not chemically bonded and can be separated physically.
Homogeneous mixtures :
Uniform composition throughout, no visible boundaries.
Examples: Saltwater, air.
Heterogeneous mixtures :
Non-uniform composition with visible phases or boundaries.
Examples: Sand and water, oil and water.
Separation Techniques: The video concludes by introducing methods to separate components of both homogeneous and heterogeneous mixtures, such as evaporation , distillation , and chromatography .
00:33
pure substances into elements and
00:35 compounds. And then for mixtures,
00:38 we have two types of
00:39 mixtures which are homogeneous and
00:43 heterogeneous. So in this video,
00:46 we're going to start by
00:47 looking at elements and compounds,
00:49 and then we'll get into
00:50 the differences between homogeneous and
00:54 heterogeneous mixtures.
00:56 So let's begin by looking
00:58 at elements which can be
00:59 found on the periodic table.
01:02 of the periodic table that's
01:03 found in the chemistry data
01:05 booklet. The periodic table contains
01:07 all known elements and they're
01:10 arranged in order of their
01:11 atomic number which is the
01:13 number of protons in the
01:14 nucleus of an atom. So
01:16 we have element 1, up
01:19 to 118. Elements only made
01:24 and cannot be broken down
01:26 into simpler substances by chemical
01:28 means. You can think of
01:30 elements as the building blocks
01:31 of matter, all matter is
01:33 made up of elements. Now
01:36 of course, elements can combine
01:37 to form compounds, which we
01:39 look at next. So next
01:41 we have compounds. Compounds are
01:44 more different elements chemically combined
01:47 in fixed ratios. So here
01:49 we have some examples of
01:50 compounds, we have H2O,
01:52 otherwise known as water. We
01:55 have ethanol which is C2H5OH
01:58 and then we have sodium
02:01 chloride on the right which
02:03 is otherwise known as salt.
02:06 So these are all examples
02:07 of compounds because they are
02:10 more different elements and they
02:11 are chemically combined. In other
02:13 words the atoms or ions
02:15 are bonded by chemical bonds.
02:18 The atoms also occur in
02:20 ratios for example in water
02:22 there's one oxygen to two
02:25 hydrogen atoms in ethanol there's
02:27 two carbons to six hydrogens
02:30 to one oxygen and in
02:32 sodium chloride it's a one
02:34 -to -one ratio of the
02:35 ions the sodium ion and
02:37 the chloride ion. An important
02:40 point about compounds is that
02:41 they have different properties from
02:43 the elements from which they
02:45 are made. For example here
02:47 we have the chemical reaction
02:48 between sodium and chlorine to
02:52 produce sodium chloride and the
02:56 properties of the elements. So
02:58 we have sodium, which is
03:00 a silver metal. We have
03:01 chlorine, which is a poisonous
03:02 gas. When they react together,
03:05 they form sodium chloride, which
03:09 relatively small amounts. So the
03:12 idea here is that the
03:13 properties of the compound are
03:15 very different from the elements
03:16 from which the compound is
03:18 made. So next we look
03:20 at homogeneous and heterogeneous mixtures.
03:23 So we have homogeneous on
03:24 the left and heterogeneous on
03:27 the right. Mixtures contain more
03:30 than one element or compound
03:31 in no fixed ratio. The
03:34 components of a mixture are
03:35 not chemically bonded together, therefore
03:37 they can be separated by
03:39 physical means. Some examples of
03:41 homogeneous mixtures include salt water,
03:45 and air. So salt water
03:50 contains salt dissolved in water
03:52 to make an aquaure solution
03:53 so all aquaure solutions are
03:56 homogeneous mixtures. Air is also
03:59 a homogeneous mixture and it's
04:00 basically a mixture of gases
04:02 such as nitrogen, oxygen and
04:04 some carbon dioxide amongst others.
04:08 Homogeneous mixtures have no visible
04:10 phases or boundaries so for
04:13 For example, if you look
04:15 water, it looks like it's
04:17 just pure water because you
04:20 can't see the salt because
04:22 the salt is dissolved in
04:24 the water. They also have
04:26 a constant composition throughout and
04:29 this means that they are
04:32 the same composition wherever you
04:34 take the sample from. So
04:36 if you take, for example,
04:38 going back to the glass
04:41 You take some salt water
04:42 from the top, if you
04:43 take the salt water from
04:44 the bottom, the composition of
04:46 that salt water will be
04:48 the same wherever you take
04:49 it. So, moving on to
04:52 heterogeneous mixtures. So, two examples
04:55 are sand and water. If
04:58 sand and water together, you'll
05:00 notice that the sand does
05:01 not dissolve in the water.
05:02 And the second example is
05:04 oil and water. So, if
05:07 oil and water, you'll notice
05:09 stays on top and the
05:10 water stays at the bottom.
05:12 So both these are examples
05:13 of heterogeneous mixtures. So heterogeneous
05:17 mixtures have visible phases or
05:19 boundaries. If you look at
05:23 water, you notice the oil
05:25 on the top, the water
05:26 at the bottom. So that's
05:27 a visible phase or a
05:28 boundary between the two phases,
05:31 the oil and the water.
05:33 The same for sand and
05:34 water, the sand will be
05:35 at the bottom, the water
05:37 visible phase or boundary between
05:39 the sand and the water.
05:42 And heterogeneous mixtures do not
05:44 have a constant composition throughout.
05:50 this diagram here, if we
05:51 take some sample from the
05:53 lower portion of the mixture,
05:54 it'll be the sand, for
05:57 example. And if you take
05:58 from the upper portion of
05:59 the mixture, it'll be the
06:01 water. So the composition is
06:03 not the same throughout a
06:05 this mixture. So next we're
06:07 going to have a look
06:08 at some separation methods to
06:10 separate the components of a
06:11 homogeneous and a heterogeneous mixture.