Types of pure substances - class-VIII
types of pure substances
Questions
Which of the following is/are example(s) of mixtures?
- Air
- $Fe + S$
- Bronze
- All of the above
A compound is always ______ whereas a mixture is :
- Heterogenous, both heterogenous and homogenous
- Homogenous, heterogenous
- Homogenous, Both homogenous and heterogenous
- None of above
Which of the following is a pure gas?
- Ntural gas
- Water gas
- Laughing gas
- Coal gas
Which of the following obey the law of constant proportions in their formation?
- Mixtures
- Compounds
- Elements
- Colloids
Among the following, which is\are the difference between compound and mixture?
- The constituents of a compound can be separated only by chemical methods.
The constituents of a mixture can be separated easily by physical methods. - Compounds are pure substances.
Mixtures are impure substances. - The constituents of a compound are present in a fixed ratio.
The constituents of a mixture are present in varying ratios. - All of above
________is chemically mixed whereas_______is physically combined.
- Element, compound
- Compound, mixture
- Mixture, compound
- Mixture, element
Which of the following is not a property of mixtures?
- Components of mixtures are present in a varying proportions
- They are always homogeneous
- The components of mixtures retain their original properties
- The components of mixtures can be separated by physical means
Which of the following methods can be used to separate hydrogen and oxygen in water?
- Boiling
- Electrolysis
- Distillation
- None of the above
Each component of a ______ retains its individual properties.
- Compound
- Element
- Mixture
- Solute
Which of the following is not an example of compound?
- Brass
- Air
- Bitumen
- All of the above
Mixture is different from a compound. True or false?
- True
- False
The components present in mixtures are in :
- fixed proportion
- variable proportion
- Both A and B
- None of the above
Which of the following is not a property of mixture?
- Does not have a sharp melting or boiling point
- Heat is taken in or given out in the preparation
- Can be separated by physical means
- May be homogeneous or heterogeneous
Which of the following statement is incorrect?
- In compounds components are present in definite proportion whereas in mixtures components are present in varying proportion
- Compounds are homogenous whereas mixtures are mostly heterogeneous
- Particles in a compound are generally of same kind whereas in mixtures they are of different kind
- None of the above
Which of the following is a characteristic property of both mixtures and compounds?
- Their properties are same as those of their components
- Energy is released when they are formed
- Their masses are equal to the sum of the masses of their components
- They contain the components in fixed proportions
Ionic compounds have ____ melting and boiling points whereas covalent compounds have _____ melting and boiling point.
- low, high
- moderate, low
- high, low
- moderate, high
Which of the following can give further simplification using ordinary means?
- An element or a mixture
- A mixture or a compound
- A mixture or an atom
- An element or a compound
A commercial cake is :
- a molecule
- a mixture of compounds
- an isotope
- an isomer
- an acid salt