Knowledge Questions Flashcards
(26 cards)
What is an element?
Elements are substances made of only one type of atom; they cannot be broken down to simpler substances
What are some examples of elements that are metals
iron,
copper,
silver,
mercury,
lead,
aluminum,
gold,
platinum,
zinc,
nickel and
tin
What are some examples of elements that are non-metals.
hydrogen,
helium,
nitrogen,
oxygen,
fluorine,
neon,
chlorine,
argon,
krypton,
xenon and
radon
How many natural elements are there?
There are about 110 elements, 90 are naturally occurring.
How many man-made elements are there?
There are about 110 elements, 20 are man-made occurring.
What is an atom? Where are the following sub-atomic particles located within the Atom – Protons? Neutrons Electrons?
An atom is the smallest part of a substance that cannot be broken down chemically.
Each atom has a nucleus (center) made up of protons (positive particles) and neutrons (particles with no charge).
Each atom has three parts (called sub-atomic particles) –
* protons (1+ charged particle)
* neutrons (uncharged particle) and
* electrons (1- charged particle).
What is a molecule?
Molecules are substances made of at least two atoms. Molecules can be either elements (like oxygen O2) or compounds (like water H2O)
What is a compound?
Compounds are substances made of at least two different elements; they can be broken down to simpler substances
What is a mixture?
A mixture is a physical combination of two or more substances that aren’t chemically joined. For example, water and salt are separate substances that, once mixed, create a mixture: seawater.
What is the difference between Mass and Weight? How does taking something from earth to the moon affect each?
The difference between a mass and a weight is:
* Mass is the amount of matter present in any object or body
* Weight is the measure of the force of gravity on an object.
When we take something from earth to the moon it affects mass and weight by:
* Mass does not change whether it is measured on earth or on the moon
* Weight can change depending upon the gravitational pull for example you may weigh 100km on Earth, but in outer space you would be weightless or your weight is reduced to one-sixth that of on Earth ie. 16.6kg
What is Density? What is the unit of measurement for Density? What unit of measurement of liquid is 1 cm³ the same as?
- Density is a measure of how much mass there is in a particular volume. Formula D = m/v
- The unit if measure of density is Density has the units of mass divided by volume such as grams per centimeters cube (g/cm3) or kilograms per liter (kg/l).
- The unit of measurement if liquid is 1 cm³ the same as A cubic centimeter (cm3) is a unit of volume in the metric system, equivalent to one milliliter or one thousandth of a liter.
What are the differences between Metals and Non metals? Highlight Properties/ characteristics and location on the Periodic Table.
- Metals are all solids (except for mercury) they are electrical conductors, are shiny, are malleable (bendable) and can be reshaped
- Non-metals are poor electrical conductors, mostly gases.
The periodic table has the metal elements toward the left and the non-metals to the right; the metals out-numbering the non-metals
How are Elements symbols chosen?
Element names and symbols are determined by the International Union of Pure and Applied Chemistry (IUPAC).
Sometimes they are related to their Greek Name or Latin Name
Approximately how many elements are there on the Periodic Table? How many are naturally occurring? How many are man-made (synthetic)?
There are about 110 elements, 90 are naturally occurring, 20 are man-made or synthetic
How many atoms are there in each molecule of H2S04
There are 7
- 2 x hydrogen
- 1 x sulphur
- 4 x oxygen
How many different elements are there in each molecule of H20
There are 2
- 2 x hydrogen
- 1 x oxygen
How many different kinds of atoms does a bar of pure gold contain?
Only one, gold AU
A rock has a Mass (g) of 420. It is placed in a cylinder of water containing 120ml, and the water level rises to 128ml. What is the volume of the Rock? What is the Density of the Rock?
Volume = 8ml
D= M/V = 52.5
Rank the following substances from least dense to most dense; Water, Steel, Oil, Cork, Air.
Order of densities – Air, cork, oil, water, steel
An unknown substance produces a green flame when heated. From the colour of the flame, what metal can we determine is present within the substance?
Aluminium, Copper or Copper Sulfate
Why do the symbols for some elements contain two letters? Why do you think the second letter is not a capital? (think about how formulas are written).
The chemical symbols for the elements are one or two letters (capital then lower case) based on, mostly, English spelling but sometimes foreign spelling.
If an element has a single English letter as a symbol, it should be written in the upper case. 2.
If an element has a two-letter symbol, the first letter should be written in the upper case and the second letter in the lower case.
What causes sound? How are frequency and vibration connected?
Sound is a type of energy made by vibrations. When an object vibrates, it causes movement in surrounding air molecules. These molecules bump into the molecules close to them, causing them to vibrate as well
The number of vibrations per second is known as the frequency, measured in Hertz (1 Hz = 1 vibration per second).
Frequency. A vibrating object moves back and forth from its normal stationary position. A complete cycle of vibration occurs when the object moves from one extreme position to the other extreme, and back again. The number of cycles that a vibrating object completes in one second is called frequency.
How is the loudness of sound measured? How is the scale of this unit different to other scales?
The loudness of sound is measured in decibels.
Draw what a sound wave looks like. Describe how the particles of matter move when sound waves pass through.
