Pls help !! it’s a timed quiz answer

In which type of mirror do you see the most realistic virtual image

ICE Princess25 [194]

Phan

convex

concave

duplex

8 0

2 years ago

Ethanol (c2h5oh) melts at -114Â°c. the enthalpy of fusion is 5.02 kj/mol. the specific heats of solid and liquid ethanol are 0.9

maria [59]

You'll want to add three amounts of heat.

(1) Specific heat of lowering the temperature from -135°C to the melting point -114°C
(2) Latent heat of fusion/melting
(3) Specific heat of elevating the temperature from -114°C to -50°C

(1) E = mCΔT = (25 g)(0.97 J/g·°C)(1 kJ/1000 J)(-114 - -135) = 0.509 kJ
(2) E = mΔH = (25 g)(5.02 kJ/mol)(1 mol/46.07 g ethanol) = 2.724 kJ
(3) E = mCΔT = (25 g)(2.3 J/g·°C)(1 kJ/1000 J)(-50 - -114) = 3.68 kJ

Summing up all energies, the answer is 6.913 kJ.

7 0

3 years ago

Why is oxygen crucial to living things?

KATRIN_1 [288]

Oxygen is something that activated Cellar Reapiration that convets nutrients into energy (ATP).

6 0

3 years ago

A steel container with a movable piston contains 2.00 g of helium which was held at a constant temperature of 25 °C. Additional

shtirl [24]

Answer: D) 1.00 g

Explanation:

According to the Avogadro's law, the volume of gas is directly proportional to the number of moles of gas at same pressure and temperature. That means,

$V\propto n$

or,

$\frac{V_1}{V_2}=\frac{n_1}{n_2}$

where,

$V_1$ = initial volume of gas = 2.00 L

$V_2$ = final volume of gas = 3.00 L

$n_1$ = initial moles of gas = $\frac{\text {Given mass of helium}}{\text {molar mass of helium}}=\frac{2.00g}{4g/mol}=0.500mol$

$n_2$ = final moles of gas = ?

Now we put all the given values in this formula, we get

$\frac{2.00L}{3.00L}=\frac{0.500mol}{n_2}$

$n_2=0.75mole$

Mass of helium = $moles\times {\text {molar mass}}=0.75\times 4=3.00g$

Thus mass of helium added = (3.00-2.00) g = 1.00 g

4 0

2 years ago

Which of the following is true concerning ψ²? A) ψ² describes the probability of finding an electron in space. B) ψ² describes t

Ilia_Sergeevich [38]

Answer:

A) ψ² describes the probability of finding an electron in space.

Explanation:

The Austrian physicist Erwin Schrödinger formulated an equation that describes the behavior and energies of submicroscopic particles in general.

The Schrödinger equation incorporates both particle behavior, in terms of mass m, and wave behavior, in terms of a wave function ψ, which depends on the location in space of the system (such as an electron in an atom).

The probability of finding the electron in a certain region in space is proportional to the square of the wave function, ψ². According to wave theory, the intensity of light is proportional to the square of the amplitude of the wave, or ψ². The most likely place to find a photon is where the intensity is greatest, that is, where the value of ψ² is greatest. A similar argument associates ψ² with the likelihood of finding an electron in regions surrounding the nucleus.

5 0

2 years ago