yes, a heterogeneous mixture.
Is it a mixture
A mixture of oil and water is a mixture, not an element. If by substance you mean not a pure substance (element or compound), then oil and water would be a substance (that is a mixture). If you mean oil and water separately, then oil is a mixture of hydrocarbons, and water is a compound (pure substance).
Oil is a mixture of hydrocarbons.
Oil and vinegar is a heterogeneous mixture.
Water and oil is a heterogeneous mixture. Oil can be separated from water via specific methods. That's why a combination of water and oil is heterogeneous.
Water and oil do not mix with each other. It is a mixture.
If the sugar does not dissolve it the oil, then it is not
The oil-water mixture is not homogeneous.
Oil and Vinegar do not dissolve in each other, therefore it is a mixture.
Yes as The amount of emulsifier in the mixture of water and oil is increased the time taken for the oil and water to separate is increased.
No. Oil and water would form a heterogeneous mixture. A solution is a homogeneous mixture.
It is neither, it is an element