Rauda wants to separate 2 liquids. Liquid A has a boiling point of 65C and liquid B has a boiling poit of 95C. She sets up a fractional distillation. Which liquid is collected first?
Liquid A, because it has the lower boiling point, it comes out first.
The periodic table organizes elements in groups based on what?
reactivity or valence electrons
Generally, what is the ionic charge on group 6 ions?
-2
Throughout the experiment the volume of hydrogen and the volume of oxygen are measured at two-minute intervals. Describe what the results show about the volumes of hydrogen and of oxygen produced in this experiment.
A description to include • volumes going up: (oxygen/ hydrogen/ gas) increase (with time) / volume (directly) proportional to time (1) • quantitative comparing
Is chlorine an alkali metal, alkaline Earth metal, halogen or noble gas?
halogen
How many electrons are there in a chloride ion (Cl-)?
18
what is the word equation for the following
sodium hydroxide + hydrochloric acid sodium chloride and water
An atom of element X has an atomic number of 119 and a mass number of 319. How many electrons does it have?
119
Explain why relative atomic masses of some elements are whole numbers, but those of some other elements, for example chlorine, are not.
Some elements have different isotopes, so their relative atomic masses are a weighted mean value.
What does the symbol Na stand for?
sodium
What is a chemical test for hydrogen gas?
squeaky pop test
the horizontal lines on the periodic table are called
periods
In fractional distillation, which would come out first? (ethane, pentane or decane)
ethane
Name of this structure?
methylbutane
Which two elements on the periodic table are liquids at room temperature?
bromine and mercury
Why is iron used in the Haber process?
it acts as a catayst
For an atom of atomic number 137, how many electrons does it contain?
Calculate the relative formula mass of calcium carbonate, CaCO3. (relative atomic masses: C = 12, O = 16, Ca = 40)
100
Which of the following is NOT a diatomic molecule? hydrogen, bromine, phophorous, nitrogen or
phosphorous
What is an advantage of having internationally agreed hazard symbols?
the hazards associated with the use of a substance will be understood in any country
An atom of element X has an atomic number of 119 and a mass number of 319. How many protons does it have?
119
Calculate the relative formula mass of calcium carbonate, CaCO3. (relative atomic masses: C = 12, O = 16, Ca = 40)
100 (amu or g/mol)
Some metal objects are electroplated. State two reasons for electroplating a metal object.
Any two • improves the appearance/ shiny (1) • improves resistance to corrosion/ does not corrode/ prevents reaction with prevents oxi; Any two from: • improve
An atom of element X has an atomic number of 119 and a mass number of 319. How many neutrons does it have?
200
Explain why the pH of a hydrochloric acid increases when pure water is added
the pH increases as the water dilutes the acid. This is because hydrogen ions are less concentrated
Definition of catalyst: a substance that speeds up a reaction without altering the ________(a) and is unchanged _______(b)
(a) products (b) chemically
Place the following pH values in order of increasing acidity: 4,1,7, 12, 6
12<7<6<4<1
) 8.000 g of CaCO3 was heated strongly for about 10 minutes. 6.213 g of solid remained. Calculate the mass of carbon dioxide gas given off.
8.000- 6.213 = (1.787) (g)
Write the formula for magnesium phosphide
Mg3P2
What is the name of this compound?
sodium dihydrogen phosphate monohydrate
What is the electron configuration of nitrogen (atomic #7)
2.5
Which subatomic particle has the lowest mass?
electron
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