Tomato Juice with a Spoon. Question by D-rock: What is the difference between pure substances, homogeneous mixtures and heterogeneous mixtures? ? I have troubles classifying if something is like a mixture. Like tomato juice is a heterogeneous mixture. I cant differ thistle them the best. Best answer: Answer by AnonymousA pure substance is like water it has definite amounts of the chemicals H and O so that you get H20. They can be elements or compounds as well. Some other examples are Diamond which is Carbon. A homogeneous mixture is uniform throughout the mixture. They… Read Article →