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Jlenok [28]
3 years ago
11

Which statement best describes why a machine is useful? A machine does a greater amount of work than the amount of work that is

done on it. A machine does a smaller amount of work than the amount of work that is done on it. A machine can decrease both the input force and the input distance needed to do a given amount of work. A machine can decrease either the input force or the input distance needed to do a given amount of work.
Chemistry
2 answers:
malfutka [58]3 years ago
8 0

"A machine can decrease either the input force or the input distance needed to do a given amount of work" is the best statement that describes why a machine is useful.

Answer: Option D

<u>Explanation :</u>

A machine is simply defined as a device that helps humans, helping them to transfer the required amount of force to compete any task, changing the direction of motion, increasing the magnitude of force to complete any task, reduce the time or distance needed to cover while performing any task.

Machines can be simple mechanical device or a combination of multiple mechanical or technical devices to reduce the amount of input force or increase the output.

Ilya [14]3 years ago
4 0

Answer:

"A machine can decrease either the input force or the input distance needed to do a given amount of work" is the best statement that describes why a machine is useful.

Answer: D

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How do I answer and do this
Alecsey [184]

a) When the reaction takes place a yellow precipitate will be formed.

b) The law of conservation of mass is true.

<u>Explanation:</u>

a) When a lead nitrate solution is mixed with a potassium chromate solution, a yellow precipitate containing lead forms according to the equation:

Pb(NO_3)_2 (aq) + K_2CrO_4 (aq) → 2 KNO_3 (aq) + PbCrO_4(s).

b) Law of conservation of mass for the given reaction is true.

From the given table we know the mass of reactants and its products.

Law of conservation of mass is a principle when a reaction takes place in a closed system, the mass of the products and reactants in the system doesn't change.

⇒The sum of the mass of the reactants = The sum of the mass of the products.

The sum of the reactants = 128.71+128.97.

                                          = 257.68 g.

The sum of the products = 154.10+103.58.

                                          = 257.68 g.

Thus law of conservation of mass is true for the above reaction.

3 0
3 years ago
Sulfur dioxide and oxygen react to form sulfur trioxide during one of the key steps in sulfuric acid synthesis. An industrial ch
mamaluj [8]

Answer:

Explanation:

From the given information:

The equation for the reaction can be represented as:

2SO_2 + O_2 \to 2SO_3

The I.C.E table can be represented as:

                     2SO₂              O₂                   2SO₃

Initial:             14                  2.6                     0

Change:        -2x                -x                      +2x

Equilibrium:   14 - 2x          2.6 - x                2x

However, Since the amount of sulfur trioxide gas to be 1.6 mol.

SO₃ = 2x,

then x = 1.6/2

x = 0.8 mol

For 2SO₂; we have 14 - 2x

= 14 - 2(0.8)

= 14 - 1.6

= 12.4 mol

For O₂; we have 2.6 - x

= 2.6 - 1.6

= 1.0 mol

Thus;

[SO₂] = moles / volume = ( 12.4/50) = 0.248 M ,

[O₂] = 1/50 = 0.02 M ,  

[SO₃] = 1.6/50 = 0.032 M

Kc = [SO₃]² / [SO₂]² [O₂]

= ( 0.032²) / ( 0.248² x 0.02)

= 0.8325

Recall that; the equilibrium constant for the reaction 2SO_2 + O_2 \to 2SO_3 = 0.8325;

If we want to find:

SO_2 + \dfrac{1}{2}O_2 \to SO_3

Then:

K_c = (0.8325)^{1/2}

\mathbf{K_c = 0.912}

Since no temperature is given to use in the question, it will be impossible to find the final temperature of the mixture.

7 0
3 years ago
Which of the following chemical compounds contains two hydrogen atoms in every molecule?
mina [271]

Answer:

A. Water

Explanation:

H2O means that there are two hydrogen and one oxygen in every water molecule.

7 0
3 years ago
Science**
mina [271]

The less mass an object has, the greater its gravitational force.

8 0
3 years ago
Mg+o2 balanced eaquation
Tanya [424]

Answer:

2Mg+O2=2MgO

balanced equation

hope it helps.

5 0
3 years ago
Read 2 more answers
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