The following characteristics describe which of these terms? the substance is not uniform in appearance and each part of the mixture contains a combination of different ingredients in different ratios.

question 16 options:

heterogeneous mixtures

homogeneous mixtures

pure substance

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Answer is: heterogeneous mixtures.

1) Heterogeneous mixture is not uniform in composition.

For example, sand and small pebbles, proportions of its components (in this mixture particles of different colors and size) vary throughout the sample.

2) Homogeneous mixture (solution if it is liquid) has the same proporties of its components throughout any given sample.

For example, if we have mixture of water and alcohol ethanol, we can separate water and ethanol with distillation (process of heating and cooling). Ethanol and water have different boiling points (physical property).

3) Pure substance is made of only one type of atom or only one type of molecule, it has definite and constant composition with distinct chemical properties.

answer: enthalpy

explanation:

for a exothermic reaction, the energy is released i.e. the energy of the products is lower than the energy of the reactants.

= enthaply

= energy of products

= energy of reactants

as , thus comes out to be negative. negative value of enthalpy shows that the reaction is exothermic.

bcde is the incorrect answer it is a