What proves that a given metal bar is a permanent magnet?

Question

What proves that a given metal bar is a permanent magnet?
    A It attracts both ends of a compass needle.
    B It attracts one end of another magnet.
    C It conducts electricity.
    D It repels one end of another magnet.

1.15 A bar magnet is moved into a solenoid (stationary coil) and an e.m.f is induced.
	 
    Which change increases the induced e.m.f.?
    A Move the magnet faster.
    B Reduce the number of turns in the solenoid.
    C Reverse the direction of the magnet.
    D Use a sensitive centre-zero millivoltmeter.

1.16 Which of the following is a property of beta particles?
    A can only be stopped by lead or concrete
    B deflect towards the negative plate
    C deflect towards the positive plate
    D have higher penetrating ability

1.17 A certain element has two isotopes.
    Which row compares the nucleon numbers and the proton numbers of these 
    isotopes?

1.18 The diagram shows the result of a chromatography experiment. T and S are the 
    mixtures being tested. 1, 2, 3 and 4 are single substances used as references.
	 
    Which substances are present in both sample S and in sample T?
    A 1 and 2
    B 1 and 4
    C 2 and 3
    D 2 and 4

1.19 Which line in the table gives the properties of Group VII elements

1.20 The properties of element X are listed below.
     I. It reacts slowly with water.
     II. It forms coloured compounds.
     III. It forms two types of ions.
      IV. It conducts electricity.
    Which properties shows that element X is a transition metal?
    A I and II
    B II and III
    C II and IV
    D III and IV

1.21 Which statement is correct when referring to graphite and wrong when referring to
    diamond?
    A It is an allotrope of carbon.
    B It is a good conductor of electricity.
    C It is the hardest substance known.
    D It has a very high melting point.

1.22 Which mixture can be separated by adding water, stirring and filtering?
     A calcium chloride and sodium chloride
     B copper and magnesium
     C lead chloride and sodium carbonate
     D silver chloride and sodium chloride

1.23 What gas is produced when a metal reacts with water?
    A carbon dioxide
    B helium
    C hydrogen
    D methane has a very high melting point.

1.24 What is the main ore of copper found in Namibia?
    A bauxite
    B chalcopyrite
    C haematite
    D galena

1.25 In the extraction of aluminium, cryolite is added to the aluminium ore.
    What is the reason for adding the cryolite?
    A To allow the electrolysis to take place at a lower temperature.
    B To decrease the malleability and the ductility of aluminium.
    C To lower the density of aluminium oxide.
    D To slow down the reaction between oxygen and carbon electrodes.

1.26 What type of substance is bronze?
    A  an alloy
    B a compound
    C an element
    D a salt

1.27 A sample of clean, dry air is passed over hot copper until all the oxygen in the air 
    reacts with the copper.
      
    What will be the remaining volume of air after the experiment?
    A 20 cm3
    B 21 cm3
    C 79 cm3
    D 80 cm3

1.28 Which fraction of crude oil is used for making roads?
    A bitumen
    B diesel
    C paraffin
    D wax

1.29 Which statement best explains why carbon monoxide is a pollutant gas?
    A It dissolves in rain water and causes acid rain.
    B It contribute to global warming.
    C It is a colourless and odourless gas.
    D It is absorbed in animal blood in preference of oxygen.

GPT-4o mini · Answer

Below are the answers to the questions provided:

What proves that a given metal bar is a permanent magnet?
- B It attracts one end of another magnet.
Which change increases the induced e.m.f.?
- A Move the magnet faster.
Which of the following is a property of beta particles?
- B deflect towards the negative plate.
A certain element has two isotopes. Which row compares the nucleon numbers and the proton numbers of these isotopes?
- (This question lacks specific isotopes to compare, please provide more details.)
Which substances are present in both sample S and in sample T?
- D 2 and 4 (This answer assumes that substances 2 and 4 are visible in both chromatograms based on the provided context.)
Which line in the table gives the properties of Group VII elements?
- (This question lacks the actual table, please provide more details.)
Which properties show that element X is a transition metal?
- D III and IV (Transition metals usually show variable valency and can conduct electricity.)
Which statement is correct when referring to graphite and wrong when referring to diamond?
- B It is a good conductor of electricity.
Which mixture can be separated by adding water, stirring and filtering?
- D silver chloride and sodium chloride (Silver chloride is insoluble in water, while sodium chloride is soluble.)
What gas is produced when a metal reacts with water?
- C hydrogen.
What is the main ore of copper found in Namibia?
- B chalcopyrite.
What is the reason for adding the cryolite in the extraction of aluminium?
- A To allow the electrolysis to take place at a lower temperature.
What type of substance is bronze?
- A an alloy.
What will be the remaining volume of air after the experiment?
- C 79 cm3 (Oxygen makes up about 21% of air, so after reacting with copper, the remaining air will be primarily nitrogen.)
Which fraction of crude oil is used for making roads?
- A bitumen.
Which statement best explains why carbon monoxide is a pollutant gas?
- D It is absorbed in animal blood in preference to oxygen.

Please note that certain questions are missing necessary reference material or specific details, and thus I made assumptions based on standard scientific knowledge. If you have specific data for those questions, please provide it for more accurate answers.