In July 1928, Calouste Gulbenkian, the Anglo-Persian Oil Company, Standard

Can someone please help me answer these questions and I’ll give you brainlest!!!!!

pickupchik [31]

Explanation:

first of all open the menu

5 0

3 years ago

In an electrically heated boiler, water is boiled at 140°C by a 90 cm long, 8 mm diameter horizontal heating element immersed in

RideAnS [48]

Explanation:

The given data is as follows.

Volume of water = 0.25 $m^{3}$

Density of water = 1000 $kg/m^{3}$

Therefore, mass of water = Density × Volume

= $1000 kg/m^{3} \times 0.25 m^{3}$

= 250 kg

Initial Temperature of water ( $T_{1}$ ) = $20^{o}C$

Final temperature of water = $140^{o}C$

Heat of vaporization of water ( $dH_{v}$ ) at $140^{o}C$ is 2133 kJ/kg

Specific heat capacity of water = 4.184 kJ/kg/K

As 25% of water got evaporated at its boiling point ( $140^{o}C$ ) in 60 min.

Therefore, amount of water evaporated = 0.25 × 250 (kg) = 62.5 kg

Heat required to evaporate = Amount of water evapotaed × Heat of vaporization

= 62.5 (kg) × 2133 (kJ/kg)

= $133.3 \times 10^{3}$ kJ

All this heat was supplied in 60 min = 60(min) × 60(sec/min) = 3600 sec

Therefore, heat supplied per unit time = Heat required/time = $\frac{133.3 \times 10^{3}kJ}{3600 s}$ = 37 kJ/s or kW

The power rating of electric heating element is 37 kW.

Hence, heat required to raise the temperature from $20^{o}C$ to $140^{o}C$ of 250 kg of water = Mass of water × specific heat capacity × (140 - 20)

= 250 (kg) × 40184 (kJ/kg/K) × (140 - 20) (K)

= 125520 kJ

Time required = Heat required / Power rating

= $\frac{125520}{37}$

= 3392 sec

Time required to raise the temperature from $20^{o}C$ to $140^{o}C$ of 0.25 $m^{3}$ water is calculated as follows.

$\frac{3392 sec}{60 sec/min}$

= 56 min

Thus, we can conclude that the time required to raise the temperature is 56 min.

4 0

3 years ago

What is the pH of a solution with a [H+] of 1.0 x 10-4 M?

MaRussiya [10]

PH = -log [H+]
pH = -log (1.0x10^-4) = -(-4) = 4 or A

4 0

3 years ago

During cooling, the kinetic energy of the molecules falls. Why does this happen?

katrin [286]

During cooling, the kinetic energy of the molecules falls, because, when cooling a substace, the particles (molecules) slow down.

The kinetic energy is related to the speed, such that the lower speed the lower kinetic energy.

Particles can translate and vibrate, in the case of gases and liquids, and only vibrate (in the case of solids).

As a substance is cooled the particles get closer and the motion (translation and vibration), slows down. You can see by the equation of the kinetic energy (KE):

KE = [1/2]mass×(speed)² that as the speed is lower the KE will also be lower.

Additionally, when the cooling does not drive a change of phase (gas to liquid, liquid to solid, or solid to gas), it drives a decrease on temperature. In this case you should know that the temperature is a measure of the kinetic energy: the lower the temperature, the lower the kinetic energy.

3 0

3 years ago

Read 2 more answers

Rate law equation The rate of a chemical reaction depends on the concentrations of the reactants. For the general reaction betwe

jekas [21]

Answer: The reaction order with respect to A is 'm'

Explanation:

Order of the reaction is the sum of the concentration of terms on which the rate of the reaction actually depends. It is equal to the sum of the exponents of the molar concentration in the rate law expression.

Elementary reactions the reactions for which the order of the reaction is same as its molecularity and order with respect to each reactant is equal to its stoichiometric coefficient as represented in the balanced chemical equation.

The given chemical equation follows:

$aA+bB\rightleftharpoons cC+dD$

The rate of the above reaction is given to us as:

$Rate=k[A]^m[B]^n$

In the above rate law expression, the order with respect to the reactants is not equal to the stoichiometric coefficients. Thus, it is not an elementary reaction.

Order with respect to reactant A = m

Order with respect to reactant B = n

Hence, the reaction order with respect to A is 'm'

8 0

3 years ago