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3 years ago

Which of the following indicates that a chemical change has happened during cooking?

Chemistry

1 answer:

Vera_Pavlovna [14]3 years ago

6 0

The food darkens because the color is changing in the food.

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The carbon-carbon (C―C) bond has an average bond energy of 347 kJ/mol, which is the energy required to break one mole of C―C bon

olganol [36]

Answer:

(3) 345 nm

Explanation:

Given:

Average C-C bond energy = 347 kJ/mol

To determine:

Wavelength of photon that can break a C-C bond

Calculation:

The energy (E) of a photon is related to its wavelength (λ) by the Planck's equation:

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

where h = Planck's constant = 6.626*10⁻³⁴ Js

c = speed of light = 3*10⁸ m/s

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

$\lambda =\frac{6.626*10^{-34}Js*3*10^{8}ms^{-1}*6.023*10^{23}mol^{-1}}{347,000Jmol^{-1}}$

λ = 3.45*10⁻⁷ m

Since 1 nanometer (nm) = 10⁻⁹ m

The calculated wavelength corresponds to 345 nm

6 0

3 years ago

A solution is made by dissolving 9.74 g of sodium sulfate in water to a final volume of 165 mL of solution. What is the weight/w

MatroZZZ [7]

Answer: The weight/weight % or percent by mass of the solute is 5.41 %.

Explanation:

Mass of the sodium sulfate,w = 9.74 g

Volume of the water = 165 mL

Density of the water = 1 g/mL

$Density=1 g/mL=\frac{\text{Mass of water}}{\text{Volume of water}}$

Mass of the water = $1 g/mL\times 165 mL=165 g$

Mass of the solution, W:

Mass of solute + Mass of solvent =9.47 g + 165 g=174.47 g

$w/w\%=\frac{w\times 100}{W}=\frac{9.45 g\times 100}{174.47 g}=5.41 \%$

The weight/weight % or percent by mass of the solute is 5.41 %.

8 0

3 years ago

HCI

Alecsey [184]

Answer:

blood

Explanation:

5 0

3 years ago

Read 2 more answers

a car is traveling at a speed of 55 mph the speed increased to 75 mph if the time needed to hange its speed is 4 seconds whats t

Savatey [412]

v = 75 mph = 33.52 m/s

u = 55 mph = 24.58 m/s

t = 4 sec

acceleration = v-u/t

= 33.52-24.58/4

= 8.94/4

= 2.235 m/s

6 0

3 years ago

HELP

Vesnalui [34]

Answer:

145.8g

Explanation:

Given parameters:

Number of moles of magnesium hydroxide = 2.5mol

Unknown:

Mass of Mg(OH)₂ = ?

Solution:

To solve this problem we use the expression below;

Mass of Mg(OH)₂ = number of moles x molar mass

Molar mass of Mg(OH)₂ = 24.3 + 2(16 + 1) = 58.3g/mol

Mass of Mg(OH)₂ = 2.5 x 58.3 = 145.8g

3 0

2 years ago