Which method of testing substances is an sure way to identify a chemical reaction?

2 answers:

6 0

. There are four different clues that indicate a chemical reaction has taken place. They are a change in color or temperature, release of a gas, or production of a precipitate.

Pani-rosa [81]3 years ago

3 0

The answer is Color change observed, or changes in color of the material.

This is one of the most common observable chemical reaction we know, simplest example is the changing of color of litmus paper when in contact with acid.

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Can someone help on this one

beks73 [17]

An action-reaction pair shows the direct relationship two objects have directly on each other. Therefore, the correct answer is C. The Moons gravity pulls on you, and your gravity pulls on the Moon because it is moon gravity-person person gravity-moon.

Choice A would be made correct if it was you pull on a drawer and the drawer pushes on you OR the table pushes on the ground and the ground pushes on the table.

Choice B would be made correct if it was a computer sits on a table and the table pushes up on the computer.

Choice D would be made correct if it was an eraser sits on a shelf and the shelf pushes up on the eraser OR the wall pushes on the shelf and the shelf pushes against the wall.

Hope this helps!!

4 0

3 years ago

What is the frequency of a mechanical wave that has a velocity of 1.70 m/s and a wavelength of 12.05 m?

zepelin [54]

Answer:

frequency = velocity divided by wavelength

Explanation:

8 0

3 years ago

Why do we have seasons? Give 3 reasons.

WARRIOR [948]

The tilt of the Earth's AXIS is the most important reason why seasons occur. We have hot summers and cold winters because of the tilt of the Earth's axis. The tilt of the Earth means the Earth will lean towards the Sun (Summer) or lean away from the Sun (Winter) 6 months later.

6 0

3 years ago

A 35 g steel ball is held by a ceiling-mounted electromagnet 4.0 m above the floor. A compressed-air cannon sits on the floor, 4

HACTEHA [7]

Answer:

7.9 m/s

Explanation:

When both balls collide, they have spent the same time for their motions.

Motion of steel ball

This is purely under gravity. It is vertical.

Initial velocity, u = 0 m/s

Distance, s = 4.0 m - 1.2 m = 2.8 m