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3 years ago

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

2 answers:

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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A ball is thrown with an initial speed vi at an angle i with the horizontal. The horizontal range of the ball is R, and the ball

adell [148]

Answer:

Part a)

$T = 2\sqrt{\frac{R}{3g}}$

Part b)

$v_x = \frac{\sqrt{3Rg}}{2}$

Part c)

$v_y = \sqrt{Rg/3}$

Part d)

$v = \frac{1}{2}\sqrt{13Rg}$

Part e)

$\theta_i = 33.7 degree$

Part f)

$H = \frac{13R}{8}$

Part g)

$X = \frac{13R}{4}$

Explanation:

Initial speed of the launch is given as

initial speed = $v_i$

angle = $\theta_i$ degree

Now the two components of the velocity

$v_x = v_i cos\theta_i$

similarly we have

$v_y = v_i sin\theta_i$

Part a)

Now we know that horizontal range is given as

$R = \frac{v_i^2 (2sin\theta_icos\theta_i)}{g}$

maximum height is given as

$H = \frac{R}{6} = \frac{v_i^2 sin^2\theta_i}{2g}$

so we have

$v_i sin\theta = \sqrt{Rg/3}$

time of flight is given as

$T = \frac{2v_isin\theta_i}{g}$

$T = \frac{2\sqrt{Rg/3}}{g}$

$T = 2\sqrt{\frac{R}{3g}}$

Part b)

Now the speed of the ball in x direction is always constant

so at the peak of its path the speed of the ball is given as

$R = v_x T$

$R = v_x 2\sqrt{\frac{R}{3g}}$

$v_x = \frac{\sqrt{3Rg}}{2}$

Part c)

Initial vertical velocity is given as

$v_y = v_i sin\theta_i$

$v_i sin\theta = \sqrt{Rg/3}$

Part d)

Initial speed is given as

$v = \sqrt{v_x^2 + v_y^2}$

so we will have

$v = \sqrt{Rg/3 + 3Rg/4}$

$v = \frac{1}{2}\sqrt{13Rg}$

Part e)

Angle of projection is given as

$tan\theta_i = \frac{v_y}{v_x}$

$tan\theta_i = \frac{\sqrt{Rg/3}}{\sqrt{3Rg}/2}$

$\theta_i = 33.7 degree$

Part f)

If we throw at same speed so that it reach maximum height

then the height will be given as

$H = \frac{v^2}{2g}$

$H = \frac{13R}{8}$

Part g)

For maximum range the angle should be 45 degree

so maximum range is

$X = \frac{v^2}{g}$

$X = \frac{13R}{4}$

3 0

3 years ago

Air resistance is a nonconservative force. It always opposes the motion of an object. An airplane flies from New York to Atlanta

Lorico [155]

Answer:

is always negative

Explanation:

Air resistance is a non-conservative force it opposes the motion of an object.It is a force that is always directed opposite to the displacement.

6 0

4 years ago

Read 2 more answers

Which planets are composed more of gas than liquids and solids?

djyliett [7]

Answer:

Jovian planets

Explanation:

The gas giants, or jovian or extra-terrestrial planets are predominantly made up of gases than liquids and solids.

They are located beyond the fringes of the Asteroid belts which is the zone between the inner and outer planets.

The outer planets are Jupiter, Saturn, Uranus and Neptune. These planets are made up of gases predominantly hydrogen and helium.

The inner planets called terrestrial planets are solids balls of rocks. These planets are Mercury, Venus, Earth and Mars.

5 0

3 years ago

Question 1.1. What are the properties of elements related to? (Points : 1)

laila [671]

The number of electrons that fill the outer shell

5 0

3 years ago

An iron anchor of density 7810.00 kg/m^3 appears 252 N lighter in water than in air. (a) What is the volume of the anchor?(b) Ho

RSB [31]

Answer:

(a)The volume of the iron anchor = 25.2 m³

(b)The mass of iron = 196812 kg

Explanation:

Density: This is the ratio of the mass of a body to its volume. The S.I unit of density is kg/m³

(a)

From Archimedes principle, the iron will displace a volume of water that is equal to its volume. And the weight of water displaced is equal to loss in weight or upthrust.

Therefore, Upthrust = lost in weight = weight of water displace.

Therefore, Volume of the iron = mass of water displace/density of water

Vi = m₁/D₁........................... Equation 1

Where Vi = volume of iron, m₁ = mass of water displaced, D₁ = Density of water.

Given: upthrust = 252 N, ∴ m₁ = 252/10 = 25.2 kg.

Constant: D₁ = 1.0 kg/m³

Substituting these values into equation 1,

Vi = 25.2/1.0

Vi = 25.2 m³

Therefore the volume of the iron anchor = 25.2 m³

(b)

Density of the iron = mass of the iron/volume of the iron.

Therefore, Mass of the iron = Density of the iron × volume of the iron...........................................equation 2

Given: Density of the iron = 7810 kg/m³, Volume of the iron = 25.2 m³

Substituting these values into equation 2,

Mass of the iron = 7810×25.2

Mass of the iron = 196812 kg.

Therefore the mass of iron = 196812 kg

8 0

4 years ago