Pure and Impure Substances

Is sugar a pure or impure substance ?

Which of the following is not a mixture but a pure substance?

Which of the following statements are true for pure substances ? (i) Pure substances contain only one kind of particles (ii) Pure substances may be compounds or mixtures (iii) Pure substances have the same composition throughout (iv) Pure substances can be exemplified by all elements other than nickel.

Which of the the following statements are true for pure substance ? (i) pure substance contain only one kind of particles (ii) pure substance may be compounds or mixtures (ii) pure substance have the same composition throughout (iv) pure substances can be exemplified by all elements other than nickel

Are these mixtures or pure substances?