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2 years ago

A defibrillator delivers about 300 joules per shock calculate the number of calories

Chemistry

1 answer:

Tanya [424]2 years ago

4 0

Answer:- 71.7 calories

Solution:- it is a unit conversion problem where we need to convert joules into calories.

The unit conversion for these energy units is:

1 calorie = 4.184 joule

The given energy is 300 joules and has to be converted to calories. We will show the set up using dimensional analysis.

$300joules(\frac{1calorie}{4.184joules})$

= 71.7 calories

So, the energy in calories is 71.7.

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The lock-and-key mechanism refers to

miskamm [114]

Answer:

A). The complementary shapes of an enzyme and a substrate.

Explanation:

The Lock-and-key mechanism was proposed by Emil Fischer for the first time and characterized as the metaphor which helps in elucidating the specificity of the enzymatic reactions. In this metaphor, the lock is described as the enzyme while 'key' is characterized as the substrate which the enzyme acts upon. If the key is not appropriately sized, it will not fit into the active site i.e. the keyhole of the lock or enzyme and reaction will not take place. Thus, option A is the correct answer.

5 0

3 years ago

Read 2 more answers

The decomposition of dinitrogen pentoxide, N2O5, to NO2 and O2 is a first-order reaction. At 60°C, the rate constant is 2.8 × 10

Sati [7]

Answer:

a. 113 min

Explanation:

Considering the equilibrium:-

2N₂O₅ ⇔ 4NO₂ + O₂

At t = 0 125 kPa

At t = teq 125 - 2x 4x x

Thus, total pressure = 125 - 2x + 4x + x = 125 - 3x

125 - 3x = 176 kPa

x = 17 kPa

Remaining pressure of N₂O₅ = 125 - 2*17 kPa = 91 kPa

Using integrated rate law for first order kinetics as:

$[A_t]=[A_0]e^{-kt}$

Where,

$[A_t]$ is the concentration at time t

$[A_0]$ is the initial concentration

Given that:

The rate constant, k = $2.8\times 10^{-3}$ min⁻¹

Initial concentration $[A_0]$ = 125 kPa

Final concentration $[A_t]$ = 91 kPa

Time = ?

Applying in the above equation, we get that:-

$91=125e^{-2.8\times 10^{-3}\times t}$

$125e^{-2.8\times \:10^{-3}t}=91$

$-2.8\times \:10^{-3}t=\ln \left(\frac{91}{125}\right)$

$t=113\ min$

3 0

2 years ago

Why do we use a double arrow in the dissociation equation for a weak acid answer?

Zepler [3.9K]

Answer is: because weak acids do not dissociate completely.

The strength of an Arrhenius acid determines percentage of ionization of acid and the number of H⁺ ions formed. 
Strong acids completely ionize in water and give large amount ofhydrogen ions (H⁺), so we use only one arrow, because reaction goes in one direction and there no molecules of acid in solution.

For example hydrochloric acid: HCl(aq) → H⁺(aq) + Cl⁻(aq).

Weak acid partially ionize in water and give only a few hydrogen ions (H⁺), in the solution there molecules of acid and ions.

For example cyanide acid: HCN(aq) ⇄ H⁺(aq) + CN⁻(aq).

4 0

2 years ago

what happens to the radius of the atoms of an element as you go towards the right in a row of the periodic table ?

Olegator [25]

Answer:

It decreases

Explanation:

As one moves from left to right on the periodic table, the radius of atoms reduces due to the nuclear pull.

The size of an atom estimated by the atomic radius is taken as half of the internuclear distance between the two covalently bonded atoms of non-metallic elements.
Across a period, atomic radius decreases progressively from left to right.
This is due to the increasing nuclear charge without attendant increase in the number of electronic shell.

7 0

2 years ago

What does it mean if you titrated the acid to a 'hot pink' color All of these

Murrr4er [49]

Answer: Too much base was added

i guessed

Explanation:

3 0

2 years ago