Damp litmus paper is used to test for chlorine gas.
Which statement describes the correct result of the test for chlorine gas?
Damp blue litmus paper turns red then white.
Damp blue litmus paper turns white then red.
Damp red litmus paper turns blue then white.
Damp red litmus paper turns white then blue.
Did this page help you?
A student adds sodium hydroxide solution to a small sample of copper(II) chloride solution.
A precipitate is made.
What is the colour of the precipitate?
Blue
Green
Orange
White
Did this page help you?
Which statement about a mass spectrum of a molecule is correct?
Each peak represents an atom in the molecule.
The charge to mass ratio of the molecular ion peak is equal to the relative formula mass of the molecule.
The peak with the highest relative abundance represents the molecular ion.
The peak on the far right of the spectrum represents the molecular ion.
Did this page help you?
During the electrolysis of brine, chlorine gas forms at one electrode.
2Cl- (aq) format('truetype')%3Bfont-weight%3Anormal%3Bfont-style%3Anormal%3B%7D%3C%2Fstyle%3E%3C%2Fdefs%3E%3Ctext%20font-family%3D%22math12bba9f4124283edd644799e0ce%22%20font-size%3D%2216%22%20text-anchor%3D%22middle%22%20x%3D%2210.5%22%20y%3D%2216%22%3E%26%23x2192%3B%3C%2Ftext%3E%3C%2Fsvg%3E)
Cl2 (g) + 2e-
Which test would be most appropriate to confirm that chlorine gas was produced?
Collect the gas and see if it extinguishes a glowing splint
Collect the gas and check if it is green
Collect the gas and see if it bleaches damp litmus paper
Collect the gas and check if it smells of swimming pools
Did this page help you?
Which is the correct method for testing for hydrogen gas?
Hold the tube containing the gas upright and place a lit splint at the end of the tube
Hold the tube containing the gas upright and place a glowing splint at the end of the tube
Hold the tube containing the gas angled down and place a lit splint at the end of the tube
Hold the tube containing the gas angled down and place a glowing splint at the end of the tube
Did this page help you?
Which is not true about the test for carbon dioxide gas?
The gas is bubbled through limewater solution
Limewater is calcium hydroxide solution
The solution will turn cloudy due to the formation of a white precipitate
The colour will fade after a few minutes
Did this page help you?
What is the correct observation when a glowing splint is held at the entrance of a tube of pure oxygen gas?
A 'squeaky pop' sound can be heard
The glowing splint relights
The glowing splint keeps glowing
The glowing splint is immediately extinguished
Did this page help you?
The electrolysis of fresh water produces hydrogen gas and oxygen gas.
The electrolysis of salt water (brine) produces hydrogen gas and chlorine, and leaves a solution of sodium hydroxide.
Which test would not help to identify a sample as being fresh water or salt water?
A gas collected makes a 'squeaky pop' when a lit splint is held in it
A gas collected relights a glowing splint
A gas collected bleaches damp litmus paper
The pH of the solution increases
Did this page help you?
Scientists test a solution from a bottle that is known to contain a copper (II) compound.
Table 1 shows their results.
Table 1
| Test | Result |
| Flame test | Yellow flame |
| Add sodium hydroxide solution | Blue precipitate formed |
| Add dilute nitric acid followed by silver nitrate solution | Yellow precipitate formed |
Which statement below is true?
The flame test was performed incorrectly
Bromide ions are present, so the compound is CuBr2
The test tube was contaminated for the sodium hydroxide test
The copper compound in the bottle was contaminated with another metal compound
Did this page help you?
A compound is suspected of containing calcium ions, Ca2+.
Which test would not help to positively identify calcium?
| Test | Result | |
| A | Flame test | Orange-red flame |
| B | Add sodium hydroxide solution | White precipitate forms |
| C | Add nitric acid and silver nitrate | White precipitate forms |
| D | Flame photometry | Characteristic lines match the reference spectrum |
Did this page help you?
Which element is present in this flame emission spectrum?
Reference line emission spectra chart
Helium
Mercury
Hydrogen
Neon
Did this page help you?
Look at the mass spectrum of a carbon compound.
Which carbon compound is this mass spectrum from?
C4H10+
C3H5O2+
C3H8O
C4H8
Did this page help you?
A student adds a few drops of sodium hydroxide solution to an unknown solution and a blue precipitate is made.
Which metal ion is present in the original solution?
Calcium
Copper(II)
Iron(II)
Iron(III)
Did this page help you?
The table shows the stages in a flame test.
| Stage | Process |
| 1 | Dip a nichrome wire loop into the test solution |
| 2 | Observe and record the flame colour |
| 3 | Clean a nichrome wire loop with hydrochloric acid, then rinse with distilled water |
| 4 | Hold the nichrome wire loop in the edge of a roaring blue flame |
Which is the correct order for the stages in a flame test?
1, 4, 2, 3
1, 4, 3, 2
3, 1, 4, 2
3, 4, 1, 2
Did this page help you?
Which statement describes the test for chlorine gas?
A lighted splint makes a squeaky pop.
Limewater turns milky.
A glowing splint re-lights.
Damp litmus paper is bleached.
Did this page help you?
Look at the mass spectrum of a carbon compound.
Which carbon compound is the mass spectrum from?
C2H2
C2H5+
C3H7+
C4H10
Did this page help you?