7TH GRADE PRACTICE
Physics Problems: Structure of matter, Grade 7
Particles, diffusion, interaction and states of aggregation.
Here the conditions and analysis of the solution can be read without an account. In the simulator, you need to collect the same analyzes yourself: “Given,” formulas, order of steps and answer.
Problem statements
The answer options are there to check against, and the walkthrough opens under each problem.
Problem #7
Particles of matter and diffusionEvaluate the statement: Matter consists of very small particles, between which there are gaps and continuous movement.
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The sizes of molecules are much smaller than usual bodies, so their properties are determined by observed effects and special instruments.
Answer
Problem #8
Particles of matter and diffusionEvaluate the statement: the concept of “Brownian motion” means: Spontaneous mutual penetration of particles of contacting substances due to their thermal motion.
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Pollen under a microscope changes direction without external push, showing the chaotic thermal movement of molecules.
Answer
Problem #9
Structure of matterMixing of substances is observed in four identical vessels. Where, other things being equal, will diffusion go faster?
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Answer
Problem #10
Interaction between particles and states of matterEvaluate the statement: At short distances, particles of matter simultaneously exhibit attraction and resistance to excessive proximity.
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Attraction holds the parts of the body together, and a sharp increase in repulsion prevents the solid body from being compressed to zero volume.
Answer
Problem #11
Interaction between particles and states of matterEvaluate the statement: the concept “Solid state” means: A liquid retains volume, but takes the shape of a container, and a gas does not retain its own shape or volume.
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A crystal resists changing shape because its particles are more connected and ordered than in a liquid.
Answer
Problem #12
Aggregate statesWhich property best distinguishes a gas from a liquid in a closed container?
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Answer
The theory behind these problems
Work through the topic if a problem will not give in.