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emmasim [6.3K]
3 years ago
5

What number should be substituted for the question mark to balance the equation and why is that the correct number?

Physics
2 answers:
grigory [225]3 years ago
6 0
The combustion of ethane results in the balanced equation 2C2H6 + 7O2 -> 4CO2 + H2O + energy because we see that after the combustion, the reactants have 8 + 6 = 14 Oxygen atoms in total (8 from 4CO2, 6 from 6H2O). Therefore, since there are 2 atoms of Oxygen in oxygen gas, we have 7O2 molecules in the beginning to hold the ratio true.
sergeinik [125]3 years ago
6 0
To balance an equation, we need to make sure the amount of atoms on the reactants and the products. 

How much oxygen's are on the reactants side? 

Lets count, 4*2 = 8  and 6, so 8+6 = 14

Now, start to predict the number. 

14/2 = 7

Answer: 7 is the correct answer
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3. A large crane lifts a 25,000 kg mass in the air. The amount of work that must be done by the
andreev551 [17]

\mathfrak{\huge{\orange{\underline{\underline{AnSwEr:-}}}}}

Actually Welcome to the concept of Efficiency.

Here we can see that, the Input work is given as 2.2 x 10^7 J and the efficiency is given as 22%

The efficiency is => 22% => 22/100.

so we get as,

E = W(output) /W(input)

hence, W(output) = E x W(input)

so we get as,

W(output) = (22/100) x 2.2 x 10^7

=> W(output) = 0.22 x 2.2 x 10^7 => 0.484 x 10^7

hence, W(output) = 4.84 x 10^6 J

The useful work done on the mass is 4.84 x 10^6 J

5 0
3 years ago
Q 2 Two mirrors meet at right angles. A ray of light is incident on one at an angle of 30°
serg [7]

a ray of light is incident towards a plane mirror at an angles of 30degrees with the mirror surface. what will be the angles of reflection is 60degree.

3 0
3 years ago
A model engine accelerated forward from rest along a straight track at 10.0 m/s2 for 3.0 seconds. It then accelerates coward at
Mrac [35]

Answer:

17.2 seconds

Explanation:

Given:

v₀ = 0 m/s

a₁ = 10.0 m/s²

t₁ = 3.0 s

a₂ = 16 m/s²

t₂ = 5.0 s

a₃ = -12 m/s²

v₃ = 0 m/s

Find: t

First, find v₁:

v₁ = a₁t₁ + v₀

v₁ = (10.0 m/s²) (3.0 s) + (0 m/s)

v₁ = 30 m/s

Next, find v₂:

v₂ = a₂t₂ + v₁

v₂ = (16 m/s²) (5.0 s) + (30 m/s)

v₂ = 110 m/s

Finally, find t₃:

v₃ = a₃t₃ + v₂

(0 m/s) = (-12 m/s²) t₃ + (110 m/s)

t₃ = 9.2 s

The total time is:

t = t₁ + t₂ + t₃

t = 3.0 s + 5.0 s + 9.2 s

t = 17.2 s

Round as needed.

4 0
3 years ago
Which energy output objects work with the turbine
viktelen [127]

Answer:

The energy output object that works with the turbine is the alternator (generator)

Explanation:

In energy generation the turbine receives input energy from high pressured steam, high energy water etc. Which impinges and turn the blades of the turbine, this turbine is connected by means of a shaft to the alternator that converts the rotational motion of the shaft to electrical energy through Electro magnetic induction principles and also outputs the energy for consumption.

6 0
3 years ago
A car has two horns, one emitting a frequency of 199 hz and the other emitting a frequency of 203 hz. what beat frequency do the
andriy [413]
Beat frequency, fb = |f2-f1|

That is, beat frequency is the absolute difference between two frequencies. Is is as a results of destructive and constructive inferences.

Therefore, in this case:

fb = 203 - 199 = 4 Hz
3 0
3 years ago
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