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3 years ago

A piston-cylinder apparatus has a piston of mass 2kg and diameterof

Engineering

1 answer:

iragen [17]3 years ago

6 0

Answer:

M =2.33 kg

Explanation:

given data:

mass of piston - 2kg

diameter of piston is 10 cm

height of water 30 cm

atmospheric pressure 101 kPa

water temperature = 50°C

Density of water at 50 degree celcius is 988kg/m^3

volume of cylinder is $V = A \times h$

$= \pi r^2 \times h$

$= \pi 0.05^2\times 0.3$

mass of available in the given container is

$M = V\times d$

$= volume \times density$

$= \pi 0.05^2\times 0.3 \times 988$

M =2.33 kg

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NO reacts with Br2 in the gas phase according to the following chemical equation: 2NO(g) +Br2(g)2NOBr(g) It is observed that, wh

klemol [59]

Answer:

a) $rate=r=k[NO]^{2} [Br_{2}]^{1}$

b) $k=\frac{1}{s*M^{2}}$

Explanation:

First of all you need to indicate the reaction order of each reactant ( $NO$ and $Br_{2}$ ):

1. $Br_{2}$

Note that if $Br_{2}$ concentration ( $[Br_{2} ]$ ) is reduced to 1/3 of its initial value, the rate of the reaction is also reduced to 1/3 of its initial value, it means:

$[Br_{2} ]=1/3$ then $r=1/3$

As the change in the rate of the reaction is equal to the change of the initial concentration of $Br_{2}$ , you could concluded that the reaction is first order with respect to $Br_{2}$

2. $NO$

Now, note that if $NO$ concentration ( $[NO]$ ) is multiplied by 3.69, the rate of the reaction increases by a factor of 13.6. In this case, to know the ratio could be advisable divide the rate of the reaction (13.6) over the factor whereby was multiplied the concentration (3.69), as follows:

$\frac{13.6}{3.69}=3.69$

As the result is the same factor 3.69 you could concluded that the change of the rate of reaction is proportional to the square of the concentration of A:

$r=[NO]^{2} =3.68^{2} =13.6$

It means that the reaction is second order with respect to $NO$

3. Rate Expression

Remember that the rate expression of the reactions depend on the concentration of each reactant and its order. In this case we have 2 reactants: $NO$ and $Br_{2}$ , then we have a rate law depending of 2 concentrations, as follows:

Note that the expression is the result of the concentration of each reactant raised to its reaction order (previously determined)

<em>Note: I hope that you do not mix up the use of the rates of reaction of each reactant, that is experimentally determined, with the stoichiometric coefficient, are different.</em>

4. Rate constant units (k)

Assuming concentration is expressed as $\frac{mol}{L}=M$ and time is in second, to find the units of k we need to solve an equation with units and with supporting of the rate equation previously obtained, as follows:

$r=k[NO]^{2} [Br_{2}]^{1}$

Where:

$[r]=[\frac{M}{s}]$

$[[NO]]=[M]$

$[ [Br_{2}]]=[M]$

Then:

$\frac{M}{s}=kM^{2} M^{1}$

$\frac{M}{s}=kM^{3}$

$\frac{M}{s*M^{3}}=k$

The units of the rate constant k are:

$k=\frac{1}{s*M^{2}}$

8 0

3 years ago

An electric kettle is required to heat 0.64 kg of water from 15.4°C to 98.2°C in six

skelet666 [1.2K]

Answer:

Almost done

Explanation:

I am just finishing up my work

7 0

2 years ago

Define and discuss the difference between micronutrients and macronutrients. Also, discuss their importance in the body at rest

almond37 [142]

Answer:

Macronutrients are simply nutrients the body needs in a very high amount e.g Carbohydrate.

MicroNutrients are simply nutrients the body needs but in little amount e.g Minerals.

Explanation:

So for further breakdown:

What are nutrients? Nutrients are essential elements that nourish the body in different capacities. We as humans get most of out nutrients from the food and water we ingest.

Now about Macro Nutrients: From the prefix "Macro" which means large, we can infer that macro nutrients are elements need by the body for the fundamental processes of the body, deficiency in this nutrients are very easy to spot. Examples are: Carbohydrates, Protein, Fats amd Water.

Micro Nutrients: In relation to macro nutrients this are elements that the body needs but are not needed in Large quantities. They mostly work like supporting nutrients. Most chemical activities like reaction that occur in the body are a function of micro nutrients. Defiencies in micrp nutrients may take some time to spot e.g Minerals and Vitamins

In regards to exercise: Macro nutrients are the essential ones here since they are the ones that generate energy. PS: micro nutrients dont generate energy.

In regards to rest: Both the Macro and Micro Nutrients are essentail for the overall well being of the body.

5 0

3 years ago

A thick oak wall initially at 25°C is suddenly exposed to gases for which T =800°C and h =20 W/m2.K. Answer the following questi

Schach [20]

Answer:

a) What is the surface temperature, in °C, after 400 s?

T (0,400 sec) = 800°C

b) Yes, the surface temperature is greater than the ignition temperature of oak (400°C) after 400 s

c) What is the temperature, in °C, 1 mm from the surface after 400 s?

T (1 mm, 400 sec) = 798.35°C

Explanation:

oak initial Temperature = 25°C = 298 K

oak exposed to gas of temp = 800°C = 1073 K

h = 20 W/m².K

From the book, Oak properties are e=545kg/m³ k=0.19w/m.k Cp=2385J/kg.k

Assume: Volume = 1 m³, and from energy balance the heat transfer is an unsteady state.

From energy balance: $\frac{T - T_{\infty}}{T_i - T_{\infty}} = Exp (\frac{-hA}{evCp})t$

Initial temperature wall = $T_i$

Surface temperature = T

Gas exposed temperature = $T_{\infty}$

6 0

3 years ago

10. An engineer is designing a total hip implant. She intends to make the femoral stem out of titanium because it forms a good i

creativ13 [48]

Answer:

Yes. She should be worried about corrosion. The 18-8 stainless exhibits intergranular corrosion due to high (0.08%) carbon content and gross pitting due to low molybdenum content.

Explanation: lol

8 0

3 years ago