A toy that is green under white light is illuminated by blue and green light, what color do you perceive?

A student is wearing a ring made out of pure copper. If the student accidentally dropped the ring into a beaker of solution, whi

nydimaria [60]

I might be wrong but the answer’s D.

6 0

2 years ago

What is the minimum mass of ethylene glycol (C2H6O2) that must be dissolved in 14.5 kg of water to prevent the solution from fre

Sergio [31]

Answer : The minimum mass of ethylene glycol is, 12000.2 grams.

Explanation : Given,

Molal-freezing-point-depression constant $(K_f)$ for water = $1.86^oC/m$

Mass of water (solvent) = 14.5 kg

Molar mass of ethylene glycol = 62.07 g/mole

Formula used :

$\Delta T_f=i\times K_f\times m\\\\T^o-T_s=i\times K_f\times\frac{\text{Mass of ethylene glycol}}{\text{Molar mass of ethylene glycol}\times \text{Mass of water in Kg}}$

where,

$\Delta T_f$ = change in freezing point

$\Delta T_s$ = freezing point of solution = $-12.6^oF=-24.8^oC$

Conversion used :

$^oF=\frac{9}{5}^oC+32$

$\Delta T^o$ = freezing point of water = $0^oC$

i = Van't Hoff factor = 1 (for non-electrolyte)

$K_f$ = freezing point constant for water = $1.86^oC/m$

m = molality

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

$0^oC-(-24.8^oC)=1\times (1.86^oC/m)\times \frac{\text{Mass of ethylene glycol}}{62.07g/mol\times 14.5kg}$

$\text{Mass of ethylene glycol}=12000.2g$

Therefore, the minimum mass of ethylene glycol is, 12000.2 grams.

6 0

2 years ago

According to the quantum-mechanical model for the hydrogen atom, which of the following electron transitions would produce light

gayaneshka [121]

Answer:

$2p\rightarrow 1s$

Explanation:

The energy of transition of $3p\rightarrow 1s$ is greater as compared to $2p\rightarrow 1s$ as there are more quantum levels which leads to more energy.

Also, considering the expression as:

$E=\frac {h\times c}{\lambda}$

Where,

h is Plank's constant having value $6.626\times 10^{-34}\ Js$

c is the speed of light having value $3\times 10^8\ m/s$

$\lambda$ is the wavelength

Wavelength is inversely proportional to Energy. Thus, the transition which has lower energy corresponds to higher wavelength.

<u>Thus, answer - $2p\rightarrow 1s$ </u>

7 0

3 years ago

A certain radioisotope has a half-life of 8.0 hours; how much of a 192 g sample of this radioisotope would decay after a full da

nadya68 [22]

If the half-life is 8.0 hours and there are 24 hours in a day, the radioisotope reaches its half-life 3 times.

Therefore, after a full day, there are 24 g of the sample left, and 168 g has decayed.

7 0

2 years ago

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(will give brainliest)What is the difference between a compound and a mixture?

nadya68 [22]

Mixture is physically and easily reversible, while compound are chemically combined together and another new substance are formed

3 0

3 years ago

Read 2 more answers