7. A solution which has dissolved as much solute as it can at a particular temperature

determine the final temperature of a gold nugget parentheses Mass equals 376 G parentheses that starts at 398k and loses 4.85 KJ

maw [93]

Answer:

297.23 K

Explanation:

Given that:

the mass of the gold nugget (m) = 376 g

the initial temperature $T_1$ = 398 K

amount of heat lost Q = -4.85 kJ = -4.85 × 10³

specific heat capacity (c) = 0.128 J/g° C

Using the formula for calculating the Heat energy

$Q = mc\Delta T \\ \\ Q = m\times c\times (T_2-T_1)$

$-4.85 \times 10^3 = 376 \times 0.128 \times (T_2 - 398) \\ \\ -4.85\times 10^3 = 48.128(T_2 - 398) \\ \\ \dfrac{-4.85\times 10^3}{48.128}= (T_2 - 398) \\ \\-100.77 = T_2 -398\\\\T_2 = -398 +100.77\\ \\ \mathbf{ T_2 = 297.23K}$

7 0

3 years ago

It takes______ dekaliters to make 100 L.<br><br> A.1000<br> B.1<br> C.10<br> D.0.1

otez555 [7]

Answer:

c

Explanation:

7 0

3 years ago

Ultraviolet radiation and radiation of shorter wavelengths can damage biological molecules because they carry enough energy to b

DIA [1.3K]

<h3>Answer:</h3>

Longest wavelength = 343.7 nm

<h3>Solution and Explanation:</h3>

In this question we need to first use the concept of energy of a photon.

Energy of a photon, E, is given by the formula, E = hf, where h is the plank's constant, f is the frequency.

But since, f is given by dividing speed, c, by wavelength, λ, then;

E = hc/λ

We are given 348 kJ/mol required to break carbon-carbon bonds.

We know that; 1 mole of bonds = 6.022 × 10^23 bonds.

We are required to find the longest wavelength with enough energy to break the C-C bonds.

This can be worked out in simple steps:

Step 1: Energy required to break one bond (kJ/bond)

1 mole of bonds = 6.022 × 10^23 bonds.

Therefore;

348 kJ = 6.022 × 10^23 bonds.

Thus;

1 bond = 348 kJ ÷ 6.022 × 10^23 bonds.

= 5.778 x 10^-22 kJ

But; 1000 joules = 1 kJ

Hence; energy per bond = 5.778 x 10^-19 Joules

Step 2: Energy per photon

Breaking one bond requires energy equivalent to energy of a photon.

Therefore;

1 photon = 5.778 x 10^-19 Joules

= 5.778 x 10^-19 J/photon

Step 3: Calculating the wavelength

From the equation of energy of a photon;

E = hc/λ

h is the plank's constant = 6.626 × 10^-34 J/s

c is the speed of light in vacuum = 2.9998 × 10^8 m/s

E is the energy of a photon = 5.778 x 10^-19 Joules

Therefore, making λ (wavelength) the subject;

$wavelength = \frac{hc}{E}$

$= \frac{(6.626 . 10^{-34})(92.9998.10^8) }{(5.778 .10^{-19} )}$

$= 3.437. 10^{-7} m$

= 3.437 x 10^-7 m

But; 1 nm = 10^-9 m

Thus;

wavelength = 343.7 nm

Therefore, the longest wavelength of the radiation will be 343.7 nm

5 0

3 years ago

When 3.00 g of Mg is ignited in 2.20 g of pure oxygen, what is the limiting reaction? What is the theoretical yield of MgO?

Ksivusya [100]

Cause do to Jalisa is

7 0

4 years ago

Oxalic acid is a diprotic acid. calculate the percent of oxalic acid (h2c2o4) in a solid given that a 0.7984-g sample of that so

vlada-n [284]

This method of quantitative determination of percent purity is titrimetric reactions. These reactions most commonly involve neutralization reactions between an acid and a base. Then, we look at the neutralization reaction:

H₂C₂O₄ + 2 NaOH ⇒ Na₂C₂O₄ + 2 H₂O

So, we do the stoichiometric calculations. The important data we should know is the molar mass of oxalic acid which is equal to 90 g/mol.

(0.2283 mol/L NaOH * 0.3798 L * 1 mol H₂C₂O₄/ 2mol NaOH * 90 g/mol H₂C₂O₄) ÷ 0.7984 g *100%
= 488%

This is impossible. The purity can't be more than 100%. Looking at our calculations and the balance reaction, all steps were done correctly. So, I think there is some typographical error in the given. The mass of the sample should be 7.984 g. Then, the answer would be 48.87% purity.

5 0

3 years ago

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