FREE CHEMISTRY AND STUDY GAMES ABOUT 8TH GRADE

PDF Download

FREE CHEMISTRY AND STUDY GAMES ABOUT 8TH GRADE

CHEMISTRY EXAM QUESTIONS

Qs and Ans Expert- Explanation

This Exam contains:

-Guarantee passing score -59 Questions and Answers -format set of multiple-choice -Expert- Explanation

Question 1: Brittleness

Answer:

physical property- the property where it can break without deforming or shredding the object

Question 2: Why must chemical reactions be balanced

Answer:

The law of conservation says that matter is neither created nor destroyed during a chemical reaction so the number of atoms of each element must be the same on both sides of the equation

Question 3: what are the five indicators of chemical reaction

Answer:

emission of light or heat, formation of gas, formation of precipitate, color change, emission of odor

Question 4: synthesis example

Answer:

a + b -> AB

Question 5: precicipitate

Answer:

a solid substance that forms as a result of reaction between chemicals in two liquid- ex. baking soda and vinegar

Question 6: combustion example

Answer:

C + O2-> CO2 + heat

Question 7: What is photosynthesis

Answer:

It is an endothermic reaction that absorbs energy from the sun to turn carvon dioxide and water into oxygen and glucose

Question 8: To shine or not to shine what are the catalyst

Answer:

Salt acted as a catalyst to help speed up the chemical reaction

Question 9: change in characteristic

Answer:

properties are changed by light or odor. ex. light stick

Question 10: sublimation

Answer:

when anything solid turns into a gas with out being liquid first

Question 11: What are reactants

Answer:

Are the substance at the beginning of a he iCal reaction

Question 12: color change

Answer:

when the property change from gray to brown rust- ex rust

Question 13: what are the five types of chemical reactions

Answer:

synthesis, decomposition, single replacement, double replacement, combustion

Question 14: How can you determine if the reaction is endothermic

Answer:

The temperature of the reaction mixture decrease

Question 15: double replacement example

Answer:

AB + CD -> AC + BD

Question 16: What is the law of conservation

Answer:

Mass is neither created nor destroyed during chemical reaction or physical reaction the bond between atoms in the reaction so all chemical equations must be balanced

Question 17: flammability

Answer:

Chemical property- the ability to burn

Question 18: elasticity

Answer:

physical property- the ability to be stretched or not

Question 19: Exeothermic process

Answer:

A change (a chemical reaction) that releases heat-energy is released as heat and light. More energy is given out than taken in

Question 20: Physical Properties

Answer:

a property that can be observed without changing the identity of the substance

Question 21: single replacement example

Answer:

AB + C -> AC + B

Question 22: Catalyst

Answer:

Is a substance that increases the rate of a chemical reaction without being consumed in the reaction

Question 23: What is bond energy

Answer:

The energy associated with bonds breaking

Question 24: Chemical changes

Answer:

changes matter undergoes when it becomes new or different matter

Question 25: Why were catalyst converters developed

Answer:

To help cars and trucks or machines move

Question 26: synthesis

Answer:

two or more elements or compounds combine to make a more complex substance

Question 27: Product

Answer:

The substance afterit is combined by a chemalreaction

Question 28: Example of Exothermic

Answer:

Burning fossil fuels, combustion, salt ando water