Answer:
1.) The smallest unit of an element that maintains the properties of the element is an atom.
2.) All compounds are molecules, but not all molecules are compounds.
A compound is a substance formed by the chemical combination of two or more elements in fixed proportions. Compounds have distinct properties that are different from those of their constituent elements.
A molecule is a group of two or more atoms held together by chemical bonds. Molecules can be made up of a single type of atom (such as O2 or N2) or a combination of different elements (such as H2O or CO2). Not all molecules are compounds, as some can be made up of a single type of atom.
3.) Mixtures that look the same throughout and have the same composition and properties in all parts of the mixture are called homogeneous mixtures. An example of a homogeneous mixture is salt water, where the salt is evenly dispersed in the water and cannot be seen or felt as separate particles. Other examples of homogeneous mixtures include air, sugar in water, and gasoline.
4.) A heterogeneous mixture that has particles that will mix but slowly settle out is called a suspension. In a suspension, the particles are large enough to scatter light, making the mixture appear cloudy or murky. The particles in a suspension are not evenly distributed throughout the mixture and will eventually settle to the bottom if left undisturbed for a period of time. Examples of suspensions include muddy water, orange juice with pulp, and paint.
5.) Mixtures that look different throughout and have varying composition and properties in different parts of the mixture are called heterogeneous mixtures. An example of a heterogeneous mixture is fruit salad, where different types of fruit are physically combined but remain distinct and can be separated from each other. Other examples of heterogeneous mixtures include granola, a pile of mixed rocks, and a glass of ice water with ice cubes floating in it.
6.) A heterogeneous mixture that has large particles that do not stay mixed is called a colloid. In a colloid, the particles are larger than those in a solution, but smaller than those in a suspension, and are evenly dispersed throughout the mixture. Colloids often appear homogeneous, but the particles will separate if the mixture is left undisturbed for a period of time. Examples of colloids include milk, fog, and whipped cream.
7.) A chemical change is a process in which a substance undergoes a transformation to produce one or more new substances with different chemical properties. In a chemical change, the original substances are broken down and rearranged into new substances, resulting in a permanent change. The substances produced in a chemical change cannot be easily reversed to their original form. Examples of chemical changes include burning, rusting, digestion, and rotting.
8.) A molecule is a group of two or more atoms held together by chemical bonds. When atoms bond together to form molecules, they create new substances with unique chemical and physical properties. Examples of molecules include water (H2O), carbon dioxide (CO2), and glucose (C6H12O6). These molecules are composed of chemically combined particles (atoms) that can no longer be separated into individual atoms by physical means.
9.) A substance made up of different kinds of atoms chemically combined is called a compound.
10.) Yes, mixtures can be classified based on particle size.
In general, mixtures can be classified into three categories based on particle size: solutions, suspensions, and colloids.
A solution is a homogeneous mixture of two or more substances, where the particles are small enough to be evenly dispersed throughout the mixture, giving it a uniform appearance.
A suspension is a heterogeneous mixture of larger particles that will eventually settle out if left undisturbed.
A colloid is a heterogeneous mixture with particles that are larger than those in a solution, but smaller than those in a suspension. Colloids appear homogeneous, but the particles will separate over time if left undisturbed.
This classification based on particle size is useful for understanding the behavior and properties of mixtures, as well as for separating and purifying substances.
11.) Physical changes.
12.) The substance that is dissolved to make a solution is called the solute.
13.) Homogeneous mixtures that have small particles that completely dissolve in one another are called solutions.
14.) The substance that does the dissolving in a solution is called the solvent.
15.) The substance made of elements and compounds that are not chemically combined is called a mixture.
16.) A technique used to separate a mixture of different liquids with different solubilities is called liquid-liquid extraction.
17.) A type of mixture that does have a uniform composition is called a homogeneous mixture.
18.) Elements and compounds are examples of pure substances.
P.S. I hope you learned something!