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Ugo [173]
3 years ago
7

a chemist is studying an unknown substance he can break it into its elemental only by using chemical means.Based on this observa

tion, how should the unknown substance be classified
Chemistry
1 answer:
Vanyuwa [196]3 years ago
4 0

Answer:

Compound

Explanation:

We want to know if it's a compound or a mixture.

An example of a mixture is salt water: you can heat it hot enough to boil off the water, leaving only the salt. This is a physical change, which is how you know it's a mixture.

Something like gold is a compound: if you heat it, or hit it, you'll still only have gold. You can only break it down by chemical means, which is how you know it's a compound.

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20 N force moving a box to 30 meters distance. How much work id done? if it takes 10 sec to do this work, how much power is used
dalvyx [7]

Answer:

Work done = 600 J

Power used = 60 W

Explanation:

Given:

Force acting on the box is, F=20\ N

Displacement of the box is, S=30\ m

Time taken for the work, t=10\ s

Now, we know that, work is said to be done by a force only when there is displacement caused by the force in its direction.

Here, the force acting on the box causes a displacement of 30 m in its direction. So, work done is equal to the product of force and displacement caused.

Therefore, work done on the box is given as:

Work=Force\times Displacement\\Work=F\times S\\Work=(20\ N)\times (30\ m)\\Work=600\ J

Therefore, the work done is 600 J.

Now, we know that, power is given as work done per unit time.

So, power used is given as:

Power=\frac{Work}{Time}\\\\Power=\frac{600\ J}{10\ s}\\\\Power=60\ W

Therefore, the power used is 60 W.

5 0
3 years ago
Acetylene gas (c2h2) reacts with oxygen gas (o2) to produce carbon dioxide (co2) and water vapor (h2o). how many liters of c2h2
MissTica
According to the balanced equation of the reaction:

2C2H2 + 5O2 → 4CO2 + 2H2O

So we can mention all as liters,

A) as we see that 2 liters of C2H2 react with 5 liters of oxygen to produce 4 liters of CO4 and 2 liters of H2O 

So, when we have 75L of CO2

and when we have 2 L of C2H2 reacts and gives 4 L of CO2

 2C2H2 → 4CO2 

∴ The volume of C2H2 required is:

                    = 75L / 2

                    = 37.5 L

B) and, when we have 75 L of CO2


and 4CO2 → 2H2O 

∴ the volume of H2O required is: 
                               
                            = 75 L /2
                            = 37.5 L 


C) and from the balanced equation and by  the same way:

when 5 liters O2  reacts to give 4 liters of CO2

and we have 75 L of CO2:

5 O2 → 4 CO2 

   ??  ←  75 L

∴ the volume of O2 required is:

                              = 75 *(5/4)

                              = 93.75 L



D) about the using of the number of moles the answer is: 

no, there is no need to find the number of moles as we called everything in the balanced equation by liters and use it as a liter unit to get the volume, without the need to get the number of moles.
6 0
3 years ago
Read 2 more answers
)
xenn [34]

Answer:

Its C hope it helped

Explanation:

3 0
3 years ago
When a lead acid car battery is recharged by the alternator, it acts essentially as an electrolytic cell in which solid lead(II)
lesya692 [45]

Answer: The mass of lead deposited on the cathode of the battery is 1.523 g.

Explanation:

Given: Current = 62.0 A

Time = 23.0 sec

Formula used to calculate charge is as follows.

Q = I \times t

where,

Q = charge

I = current

t = time

Substitute the values into above formula as follows.

Q = I \times t\\= 62.0 A \times 23.0 sec\\= 1426 C

It is known that 1 mole of a substance tends to deposit a charge of 96500 C. Therefore, number of moles obtained by 1426 C of charge is as follows.

Moles = \frac{1426 C}{96500 C/mol}\\= 0.0147 mol

The oxidation state of Pb in PbSO_{4} is 2. So, moles deposited by Pb is as follows.

Moles of Pb = \frac{0.0147}{2}\\= 0.00735 mol

It is known that molar mass of lead (Pb) is 207.2 g/mol. Now, mass of lead is calculated as follows.

No. of moles = \frac{mass}{molar mass}\\ 0.00735 = \frac{mass}{207.2 g/mol}\\mass = 1.523 g

Thus, we can conclude that the mass of lead deposited on the cathode of the battery is 1.523 g.

3 0
3 years ago
What are the three was main States of matter?
OleMash [197]

Answer:

liquid, solid, gas

Explanation:

7 0
4 years ago
Read 2 more answers
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