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3 years ago

Why is it important to know the velocity of an object instead of just speed?

1 answer:

8 0

Velocity helps measure the rate at which an object changes it's position in a given direction. If you were measuring a tornado, for example, you would want to know both speed and velocity to predict where as well as how fast it will travel.

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The following data was collected for the formation of ammonia (NH3) based on the following overall reaction: N2 + 3H2 = 2NH3 N2

notsponge [240]

Answer : The unit for the rate constant in the rate law for the formation of ammonia is, $M^{-2}min^{-1}$

Explanation :

Rate law is defined as the expression which expresses the rate of the reaction in terms of molar concentration of the reactants with each term raised to the power their stoichiometric coefficient of that reactant in the balanced chemical equation.

For the given chemical equation:

$N_2+3H_2\rightarrow 2NH_3$

Rate law expression for the reaction:

$\text{Rate}=k[N_2]^a[H_2]^b$

where,

a = order with respect to $N_2$

b = order with respect to $H_2$

Expression for rate law for first observation:

$0.0021=k(0.10)^a(0.10)^b$ ....(1)

Expression for rate law for second observation:

$0.0084=k(0.10)^a(0.20)^b$ ....(2)

Expression for rate law for third observation:

$0.0672=k(0.20)^a(0.40)^b$ ....(3)

Dividing 2 by 1, we get:

$\frac{0.0084}{0.0021}=\frac{k(0.10)^a(0.20)^b}{k(0.10)^a(0.10)^b}\\\\4=2^b\\b=2$

Dividing 3 by 1 and also put value of b, we get:

$\frac{0.0672}{0.0021}=\frac{k(0.20)^a(0.40)^2}{k(0.10)^a(0.10)^2}\\\\2=2^a\\a=1$

Thus, the rate law becomes:

$\text{Rate}=k[N_2]^a[H_2]^b$

$\text{Rate}=k[N_2]^1[H_2]^2$

Now, calculating the value of 'k' by using any expression.

$0.0021=k(0.10)^1(0.10)^2$

$k=2.1M^{-2}min^{-1}$

The value of the rate constant 'k' for this reaction is $2.1M^{-2}min^{-1}$

That means, the unit for the rate constant in the rate law for the formation of ammonia is, $M^{-2}min^{-1}$

7 0

3 years ago

The characteristic flame test colors of metal ions are due to atomic emission spectra. Duscuss the relationship between the abso

vesna_86 [32]

The characteristics flame test color of metal ions are because of the atomic emission spectra.

When an atom absorbs a particular wavelength radiation, the electrons within it, move from lower energy level to the higher level of energy. Such a procedure is called absorption. When this stimulated electron to come back to its ground state, it loses energy in particular color on the basis of the frequency of the absorbed radiation. Such a procedure is called emission.

As an atom exhibit, distinct levels of energy, the level close to the nucleus possess less energy in comparison to the level, which is far from the nucleus. So, electrons move from lower energy level to the higher level by attaining particular energy, and after excitation, it comes back from high energy level to a low energy level with the emission of light.

According to Planck's concept, there is a specific difference of energy between the two energy level, so such energy difference is quantized. Only those radiation are absorbed, which are equivalent to the difference of energy between the two levels.

8 0

3 years ago

Red light has a wavelength of 700 nm and a frequency of 4.3 x 10^14 s^-1. What is the energy of a single photon of red light?

BaLLatris [955]

Answer:

E = 2.85×10⁻¹⁹ J

Explanation:

Given data:

Wavelength of light = 700 nm

Frequency of light = 4.3×10¹⁴ s⁻¹

What is the energy of light = ?

Solution:

Formula:

E = h × f

h = plancks constant = 6.63×10⁻³⁴ Js

by putting values,

E = 6.63×10⁻³⁴ Js × 4.3×10¹⁴ s⁻¹

E = 28.5×10⁻²⁰ J

E = 2.85×10⁻¹⁹ J

6 0

3 years ago

If 25.8 grams of BaO dissolve in enough water to make a 212-gram solution, what is the percent by mass of the solution?

Igoryamba

The correct answer is 12.2% BaO.

The solution is found by dividing the mass of the BaO, which is 25.8 grams, by the total mass of the solution, which is 212 grams, then multiplying it by 100 to get the percentage:
$\frac{25.8}{212}*(100) =12.2%$

3 0

3 years ago

if a gas sample in a balloon occupies 1.5 L at atmospheric pressure, what would be the pressure (in mmHg) if the volume was redu

Nata [24]

Answer:

1425 mmHg.

Explanation:

The following data were obtained from the question:

Initial volume (V1) = 1.5 L

Initial pressure (P1) = 1 atm

Final volume (V2) = 0.8 L

Final pressure (P2) =?

Next, we shall determine the final pressure of the gas by using the Boyle's law equation as follow:

P1V1 = P2V2

1 × 1.5 = P2 × 0.8

1.5 = P2 × 0.8

Divide both side by 0.8

P2 = 1.5/0.8

P2 = 1.875 atm

Finally, we shall convert 1.875 atm to mmHg.

This can be obtained as follow:

1 atm = 760 mmHg

Therefore,

1.875 atm = 1.875 × 760 = 1425 mmHg.

Therefore, the new pressure of the gas is 1425 mmHg.

3 0

3 years ago