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4 years ago

Helppppppppppppppppppp me

Chemistry

1 answer:

masya89 [10]4 years ago

8 0

The answer is A.
A pure substance is pure, so it cannot be separated in most cases.

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a bright violet line occurs at 435.8 nm in the emission spectrum of mercury vapor. What amount of energy, in joules, must be rel

Readme [11.4K]

<h3>Answer:</h3>

4.56 × 10^-19 Joules

<h3>Explanation:</h3>

We are given;

Wavelength of the wave as 435.8 nm

We are required to calculate the amount of energy released by an electron.

We know that the speed of the wave, c is 2.998 × 10^8 m/s
But, c = f × λ , where f is the frequency and λ is the wavelength
Energy of a wave is given by the formula;

E = hf , where h is the plank's constant, 6.626 × 10^-34 J-s

But, f = c/λ

Therefore;

f = (2.998 × 10^8 m/s) ÷ (4.358 × 10^-7 m)

= 6.879 × 10^14 Hz

Thus;

Energy = 6.626 × 10^-34 J-s ×6.879 × 10^14 Hz

= 4.558 × 10^-19 Joules

= 4.56 × 10^-19 Joules

Therefore, the energy that must be released by the electron is 4.56 × 10^-19 Joules

7 0

3 years ago

Explain how temperature and amount of precipitation can affect the type of plants and animals found in the grassland biome?

MArishka [77]

Temperature grasslands have hot summers and cold winters. Summer temperatures can be well over 100 degrees Fahrenheit, while winter temperatures can be as low as -40 degrees Fahrenheit. They typically have between 10 and 35 inches of precipitation a year, much of it occurring in the late spring and early summer. As climate conditions shift geographically so will the distributions of many plants and animals. The relatively flat terrain of grasslands increases vulnerability to climate change impacts, because habitats and species must migrate long distances to compensate for temperature shift.

3 0

3 years ago

A chemist adds 26.5g of ammonium chloride to 10g of sodium hydroxide, which follows the reaction below. Assuming the reaction go

4vir4ik [10]

Answer : The amount of reactant left in excess is 13.1075 grams.

Explanation : Given,

Mass of $NH_4Cl$ = 26.5 g

Mass of $NaOH$ = 10 g

Molar mass of $NH_4Cl$ = 53.5 g/mole

Molar mass of $NaOH$ = 40 g/mole

First we have to calculate the moles of $NH_4Cl$ and $NaOH$ .

$\text{Moles of }NH_4Cl=\frac{\text{Mass of }NH_4Cl}{\text{Molar mass of }NH_4Cl}=\frac{26.5g}{53.5g/mole}=0.495moles$

$\text{Moles of }NaOH=\frac{\text{Mass of }NaOH}{\text{Molar mass of }NaOH}=\frac{10g}{40g/mole}=0.25moles$

Now we have to calculate the limiting and excess reagent.

The balanced chemical reaction is,

$NH_4Cl+NaOH\rightarrow NH_4OH+NaCl$

From the balanced reaction we conclude that

As, 1 mole of $NaOH$ react with 1 mole of $NH_4Cl$

So, 0.25 moles of $NaOH$ react with 0.25 moles of $NH_4Cl$

From this we conclude that, $NH_4Cl$ is an excess reagent because the given moles are greater than the required moles and $NaOH$ is a limiting reagent and it limits the formation of product.

Moles of remaining excess reactant = 0.495 - 0.25 = 0.245 moles

Now we have to calculate the mass of $NH_4Cl$ .

$\text{Mass of }NH_4Cl=\text{Moles of }NH_4Cl\times \text{Molar mass of }NH_4Cl$

$\text{Mass of }NH_4Cl=(0.245mole)\times (53.5g/mole)=13.1075g$

Therefore, the amount of reactant left in excess is 13.1075 grams.

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3 years ago

Check the statements that are a part of the early atomic theory. Check all of the boxes that apply

Shalnov [3]

What's the options? I'm confused

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3 years ago

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Whta gasses are in Neptune?

Natasha_Volkova [10]

Neptune's atmosphere is composed up of many gases. These gases include Hydrogen (80%), Helium (19%), and Methane<span> (1.5%). Some of the minor gases include trace amounts of </span>Hydrogen Deuteride<span> and </span>Ethane<span>.</span>

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3 years ago