An air sample consists of oxygen and nitrogen gas as major components. it also contains carbon dioxide and traces of some rare gases. all these gases are evenly distributed throughout the sample of air. which term or terms could be used to describe this sample of air? check all that apply.

Explanation:

The relevant definitions that you must know to answer this question are:

Pure substance: matter that has a unique fixed (invariable) uniform composition. Only elements and compounds are pure substances.

Element: matter formed by one single kind of atoms. For instance, hydrogen, oxygen, sodium. There are 118 known elements and they are all listed in the periodic table.

Compound: pure substances formed by two or more kind of atoms. For instance: H₂O, CO₂, NaOH, CH₃OH. Every compound has its own chemical compositon. There are infinetely many different compounds.

Mixture: a mixture is a combination of two or more pure substances, in any proportion. Each pure substance retains its own properties in the mixture.

Homogeneous mixture: a mixture in which the components cannot be distinguished by physical media. Alll the components are in the same phase and the compositon of the mixture is uniform.

Solutions: homogeneous mixtures.

Heterogeneous mixture: mixtures in which the individual components can be distinguished by physical media. E.g. the mixture of sand and water.

With that you can go through each choice:

a) mixture: Correct. Indeed air is a mixture because it is formed by several compounds (carbon dioxide, CO₂) and other gases.

b) heterogeneous mixture: Wrong. It is not heterogeneous because its components are evenly distributed throughout the sample of air and they cannot be distinguished one from each other by physical media.

c) homogeneous mixture: Correct. This is a homogeneous mixture, for the same reason explained in b)

d) solution: Correct. Solutions are homogeneous mixtures.

e) pure chemical substance: Wrong. Pure chemical substances are composed either by one kind of atoms or one kind of compound. Since there are several different elements and compouds this is not a pure chemical substance.

f) compound: Wrong. Carbon dioxide (CO₂) is a compound, but there are other compounds and elements present in the sample of air.

g) element: Wrong. Oxygen is an element (it has only oxygen atoms), but there are other elements and compounds.

answer: the primary difference between a hypothesis and a theory is that b hypothesis is falsifiable, but a theory has been proven to be correct. theory is an explanation of something that is happening but hypothesis is a guess of something that can happen

explanation:

answer : one can design an experiment using a liquid and an additive that can be added to the liquid and observe the chemical changes in the reaction species.

one would need a beaker which is filled with a known amount of the liquid in which thermometer is placed to measure the temperature changes; after addition of the additive to the liquid solution one can note down the temperature change and find whether the reaction is endothermic or exothermic in nature. by subtracting the initial temperature value with the final temperature one can find the temperature changes.

various combinations of liquid and additive can be used. liquid in this case can be a known quantity of water and additives can be epsom salt or without epsom salt the experiment can be conducted to notice the changes. water and ice, hydrogen peroxide and dry yeast, vinegar and baking soda,etc.