1.
A(n) ______ is NOT homogenous.
Correct Answer
A. Suspension
Explanation
A suspension is not homogenous because it is a mixture of solid particles that are dispersed in a liquid or gas. Unlike a solution, where the solute is evenly distributed throughout the solvent, in a suspension, the particles are not dissolved and can be seen with the naked eye. This lack of uniformity makes suspensions non-homogenous.
2.
The scattering of light by colloids is called ______.
Correct Answer
A. The tyndall effect
Explanation
The scattering of light by colloids is known as the Tyndall effect. When light passes through a colloid, the particles in the colloid scatter the light, making the beam visible. This effect is used to distinguish between a true solution and a colloid or suspension. In a true solution, the particles are so small that they do not scatter light, while in a colloid or suspension, the larger particles scatter the light, creating a visible beam. The Tyndall effect is commonly observed in everyday life, such as when sunlight passes through a dusty room, making the dust particles visible in the air.
3.
Smoke is an example of a ____.
Correct Answer
C. Colloid
Explanation
Smoke is an example of a colloid because it consists of small solid particles suspended in a gas. Colloids are heterogeneous mixtures where the particles do not dissolve but remain dispersed throughout the medium. In the case of smoke, the solid particles (such as carbon) are suspended in the air, creating a cloudy appearance. This is different from a solution, where the particles are dissolved and not visible, or a suspension, where the particles are larger and eventually settle down.
4.
Three examples of physical changes are _______.
Correct Answer
B. Boiling of water, bursting of a balloon, and melting of a candle
Explanation
The answer "boiling of water, bursting of a balloon, and melting of a candle" is correct because these are all examples of physical changes. In each case, the substance undergoes a change in its physical state or appearance without any change in its chemical composition. Boiling water changes it from a liquid to a gas, bursting a balloon changes its shape, and melting a candle changes it from a solid to a liquid.
5.
The color of ink is a ______.
Correct Answer
B. pHysical property
Explanation
The color of ink is a physical property because it can be observed and measured without changing the chemical composition of the ink. It is a characteristic of the ink that can be described and compared to other substances.
6.
When two or more substances are combined so that each substance maintains its own properties, the result is a(n) _____.
Correct Answer
D. Mixture
Explanation
When two or more substances are combined so that each substance maintains its own properties, the result is a mixture. In a mixture, the substances are physically combined and can be separated by physical means, such as filtration or evaporation. The individual components of the mixture do not chemically react with each other and retain their original properties.
7.
When gasoline is burned in an engine, _____.
Correct Answer
B. New substances are formed
Explanation
When gasoline is burned in an engine, new substances are formed. During the combustion process, the gasoline molecules break apart and react with oxygen to form carbon dioxide and water vapor. This chemical reaction results in the creation of new substances, specifically carbon dioxide and water, which are released as byproducts of the combustion process.
8.
_____ is another name for a homozygous mixture.
Correct Answer
C. Solution
Explanation
A solution is a homogeneous mixture in which the solute is uniformly dispersed in the solvent. In a solution, the solute particles are evenly distributed and cannot be easily separated from the solvent. Therefore, a solution can be considered as a homozygous mixture, meaning that it has a uniform composition throughout.
9.
The odor of a substance is a physical property.
Correct Answer
A. True
Explanation
The statement is true because the odor of a substance is a physical property that can be observed and measured without changing the chemical composition of the substance. Physical properties are characteristics that can be observed or measured without altering the substance's identity, and the odor falls under this category. It is a sensory perception that can vary from one substance to another and can be detected by our sense of smell.
10.
The freezing of water is a chemical change.
Correct Answer
B. False
Explanation
The freezing of water is a physical change, not a chemical change. During freezing, water molecules slow down and arrange themselves into a solid structure, but no new substances are formed. The chemical composition of water remains the same before and after freezing. Therefore, the correct answer is False.
11.
A fruit salad is a homogenous mixture.
Correct Answer
B. False
Explanation
A fruit salad is not a homogenous mixture because it contains different types of fruits, each with its own distinct properties and characteristics. The fruits in a fruit salad do not blend together to form a uniform mixture, but rather retain their individual textures, flavors, and colors. Therefore, the statement is false.
12.
Color is a physical property.
Correct Answer
A. True
Explanation
Color is a physical property because it is an inherent characteristic of an object that can be observed and measured without changing the object's chemical composition. Color is determined by the way an object reflects or absorbs certain wavelengths of light, which is a physical phenomenon. It can be quantitatively described using parameters such as hue, saturation, and brightness. Therefore, color can be classified as a physical property.