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3 years ago

Which of these is a chemical change?

Physics

2 answers:

Radda [10]3 years ago

7 0

Anything that says burned is a chemical reaction or a chemical change. Here's a burning reaction.

C2H5OH + 302 ===> 2CO2 + 3H2O

This is the equation for burning alcohol (the kind you drink). When burned, the alcohol's reaction leaves a beautiful blue flame along with CO2 and H2O on the right side.

So B is the answer.

You're not doing anything to paper if you shred it except make it smaller. It retains all of its chemical properties and almost all its physical properties.

Ice melting doesn't do anything to the water when it changes phase except you now have a puddle on the table where the ice (cube) was. But you are still dealing with water.

Metal foil is heated, again the foil is left with all its chemical properties in tact. You can reuse the foil if you are cooking potatoes in an open fire. Nothing has altered the chemical properties of the foil.

Iteru [2.4K]3 years ago

6 0

The answer is when GAS IS BURNED because when gas is burned, it cannot return into its previous state. Also, new substances are formed.

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A lamp hangs from the ceiling at a height of 2.9 m. If the lamp breaks and falls to the floor, what is its impact speed

ser-zykov [4K]

To solve this there is this website that I found that helps
I am in middle school so I have no idea how to solve this
but
this website may help considering u are in high school and u
(hopefully mind u)
know how to solve this
so to get there u google
"whats impact speed"
and click on the first thing there the website is ehow

8 0

2 years ago

A 40.0 kg wagon is towed up a hill inclined at 18.5 degrees with respect to the horizontal. The tow rope is parallel to the incl

sp2606 [1]

Answer:

7.9m/s

Explanation:

We are given that

Mass of wagon=40 kg

$\theta=18.5^{\circ}$

Tension= $140 N$

Initial velocity of wagon= $u=0$

Displacement=s=80 m

Net force applied on wagon= $F=T-mgsin\theta=140-40(9.8)sin18.5=15.7 N$

By using $g=9.8m/s^2$

$a=\frac{F}{a}=\frac{15.7}{40}=0.39m/s^2$

We know that

$v^2-u^2=2as$

Using the formula

$v^2=2\times 0.39\times 80$

$v=\sqrt{2\times 0.39\times 80}=7.9m/s$

5 0

3 years ago

Ice has a density of 0.920 g/cm3. An ice cubes mass is 100 g. What is its volume?

Tasya [4]

Answer:

$\boxed {\tt 108.695652 \ cm^3}$

Explanation:

Volume can be found by dividing the mass by the density.

$v=\frac{m}{d}$

The mass is 100 grams and density is 0.920 grams per cubic centimeters.

Therefore,

$m=100 \ g \\d= 0.920 \ g/cm^3$

Substitute the values into the formula.

$v=\frac{100 \ g}{0.920 \ g/cm^3}$

Divide. Note that the grams, or "g" will cancel each other out.

$v- 108.695652 \ cm^3$

The volume of the ice cube is 108.697652 cubic centimeters.

3 0

3 years ago

Gamma rays have more energy than X-rays. What else is true about gamma rays?

posledela

The answer is D. They have a higher frequency than X-rays.

Gamma-rays falls in the electromagnetic spectrum above, Gamma-rays have frequencies greater than 10¹⁸ cycles per second, or Hertz (Hz)

5 0

2 years ago

Why is this statement false?

koban [17]

The statement is false because as the temperature of water is decreased from 4C to 0C, <em>expansion</em> occurs.

You should understand that this is very weird behavior for any compound ... within a small temperature range, the stuff actually gets bigger as it gets colder. That's why cubes float in your sody, and bergs float in the ocean.

Water is one of only two known substances that do this. And if water didn't do it, then life on Earth would not be possible.

Hmmm....

7 0

2 years ago