Which of the following mixtures is NOT homogeneous?
Oil and water
A homogeneous mixture has a uniform composition throughout, while a heterogeneous mixture has visibly separate parts.
Oil does not dissolve in water; it forms a separate layer on top, so oil and water is a heterogeneous mixture.
Vinegar (acetic acid in water), salt water (salt dissolved in water) and air (a uniform mixture of gases) all have uniform composition and are homogeneous.
Hence, the answer is oil and water.
Who was the first scientist to use the term 'element'?
Match the compound to its respective mass ratio by elements from the table given below.
| Compound | Mass Ratio by Elements |
| 1. Water (H2O) | A. 1 : 8 |
| 2. Carbon dioxide (CO2) | B. 14 : 3 |
| 3. Ammonia (NH3) | C. 3 : 8 |
| 4. Sulphur dioxide (SO2) | D. 1 : 1 |
If hydrochloric acid (HCl) reacts with sodium hydroxide (NaOH), which ions from each reactant participate in forming water?
Which of the following most accurately represents a heterogeneous mixture?
Among the following, what has a molecular mass of 44 u?
When 16 g of oxygen is combined with 2 g of hydrogen, 18 g water is formed. This observation is in accordance with:
Methyl orange turns red in:
Why is the reaction flask corked during experiments verifying conservation of mass?
Which of the following is a heterogenous mixture?
Given that the atomic masses of C = 12 u, O = 16 u and H = 1 u, which of the following options correctly represents the molecular masses of CO2 and H2O?