Many scientist compare the parts of a cell to the parts of a factory. Do you think this comparison is fair and useful?

A 126.1-gram block of granite at 92.6°C is dropped into a tub of water at 24.7°C in an isolated system. The final temperature of

Romashka-Z-Leto [24]

The granite block transferred 4080 J of energy, and the mass of the water is 35.8 g.

1. Energy from granite block

The formula for the heat (q) transferred is

q = mCΔT

m = 126.1 g; C = 0.795 J·°C⁻¹g⁻¹; ΔT = T_f – T_i = 51.9 °C - 92.6 °C = -40.7 °C

∴ q = 126.1 g × 0.795 J·°C⁻¹g⁻¹ × (-40.7 °C) = -4080 J

The granite block transferred 4080 J.

2. Mass of water

q = mCΔT

m = q/(CΔT)

q = 4080 J; C = 4.186 J·°C⁻¹g⁻¹; ΔT = T_f – T_i = 51.9 °C – 24.7 °C = 27.2 °C

∴ m = 4080 J/(4.186 J·°C⁻¹g⁻¹ × 27.2 °C) = 35.8 g

The mass of the water is 35.8 g.

7 0

3 years ago

A gas mixture contains twice as many moles of o2 as n2. addition of 0.200 mol of argon to this mixture increases the pressure fr

pantera1 [17]

Number of moles of oxygen = x

number of moles of nitrogen = y

x = 2y

initial pressure, p1 = 0.8 atm

final pressure, p2 = 1.10 atm

At constant volume and temperature p1 / n1 = p2 / n2

=> p1 / p2 = n1 / n2

n1 = x + y = 2y + y = 3y

n2 = 0.2 + 3y

=> p1 / p2 = 3y / (0.2 + 3y)

=> 0.8 / 1.10 = 3y / (0.2 + 3y)

=> 0.8 (0.2 + 3y) = 1.10 (3y)

0.16 + 2.4y = 3.3y

=> 3.3y - 2.4y = 0.16

=> 0.9y = 0.16

=> y = 0.16 / 0.9

=. x = 2*0.16/0.9 = 0.356

Answer: 0.356 moles O2

8 0

3 years ago

How many valance electrons does group #11 have?

galina1969 [7]

It would have 11 valance electrons.

Example/Explanation:

Say we are talking about groups 10. Group 10 would have 10 valance electrons because of the atom's electronic arrangement in the periodic table.

6 0

3 years ago

When a chemical reaction is run in aqueous solution inside a calorimeter, the temperature change of the water (and Ccal) can be

Yakvenalex [24]

Answer:

The total change in enthalpy for the reaction is - 81533.6 J/mol

Explanation:

Given the data in the question;

Reaction;

HCl + NaOH → NaCl + H₂O

Where initial temperature is 21.2 °C and final temperature is 28.0 °C. Ccal is 1234.28 J

Moles of NaOH = 50.mL × 1.00 M = 50.0 mmol = 0.0500 mol

Moles of HCl = 50.mL × 1.00 M = 50.0 mmol = 0.0500 mol

so, 0.0500 moles of H₂O produced

Volume of solution = 50.mL + 50.mL = 100.0 mL

Mass of solution m = volume × density = 100.0mL × 1.0 g/mL = 100 g

now ,

Heat energy of Solution q= (mass × specific heat capacity × temp Δ) + Cal

we know that; The specific heat of water(H₂O) is 4.18 J/g°C.

so we substitute

q_soln = (100g × 4.18 × ( 28.0 °C - 21.2 °C) ) + 1234.28

q_soln = 2842.4 + 1234.28

q_soln = 4076.68 J

Enthalpy change for the neutralization is ΔH $_{neutralization}$

ΔH $_{neutralization}$ = -q_soln / mole of water produced

so we substitute

ΔH $_{neutralization}$ = -( 4076.68 J ) / 0.0500 mol

ΔH $_{neutralization}$ = - 81533.6 J/mol

Therefore, the total change in enthalpy for the reaction is - 81533.6 J/mol

6 0

3 years ago

Why ph changes disrupt protein's ionic bonds?

Inessa05 [86]

Answer:

A change in pH in the protein habitat can modify its ionic bonds because because the chemical equilibrium shifts to one side or the other depends on the modification

Explanation:

The pH influences the charge acquired by the acidic and basic groups present in the molecules. Proteins usually have groups with characteristics of acid or weak base. Therefore, they are partially ionized in solution coexisting in equilibrium different species.

The degree of ionization of the different functional groups is in relation to the pH of the medium in which they are found, since the H3O + and OH- species are part of the equilibrium situation. Therefore, according to the pH, each group with characteristics of weak acid or base present in the molecule will be ionized to a lesser or greater extent. There are extreme situations where the balance has been totally displaced in one direction, for example: under very high pH conditions (low concentration of H3O +) weak acids are considered fully ionized, so the functional group will always have an electric charge. The same goes for the bases at very low pH values. In other equilibrium situations, species of the same molecule with different load will coexist in the solution, due to the pH value of the medium in which it is found.

8 0

3 years ago