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3 years ago

I need help!!!!!!! please

Chemistry

1 answer:

lions [1.4K]3 years ago

8 0

Answer:

A. bacteria

Explanation:

can i have brainlest?

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A compound contains 38.7% K, 13.9% N, and 47.4% O by mass. What is the empirical formula of the compound?

inysia [295]

K ---> 38.7 g / 39.1 g/mol = 0.99
N ---> 13.9 g / 14.0 g/mol = 0.99
O ---> 47.4 g / 16.0 g/mol = 2.96

Divide by smallest:

K ---> 0.99 / 0.99 = 1
N ---> 0.99 / 0.99 = 1
O ---> 2.96 / 0.99 = 3

KNO3

8 0

3 years ago

Calculate the wavelength, in nanometers, of the light emitted by a hydrogen atom when its electron falls from the n = 7 to the n

Gre4nikov [31]

Answer:

The wavelength of the light emitted by a hydrogen atom for the given transition is 2166 nm.

Explanation:

The energy of nth energy levels of the H atom is given as:

$E_n = -2.18 \times 10^{-18} \times \frac{1}{n^2} J$

Energy of the seventh energy level = $E_7$

$E_7=-2.18 \times 10^{-18} \times \frac{1}{7^2} J$

$E_7=-2.18 \times 10^{-18} \times \frac{1}{7^2} J=-4.4490\times 10^{-20} J$

Energy of the seventh energy level = $E_4$

$E_4=-2.18 \times 10^{-18} \times \frac{1}{4^2} J$

$E_4=-2.18 \times 10^{-18} \times \frac{1}{16} J=-1.3625\times 10^{-19} J$

Energy of the light emitted will be equal to the energy difference of the both levels.

$E=E_7-E_4=-4.4490\times 10^{-20} J-(-1.3625\times 10^{-19} J)$

$E=9.176\times 10^{-20} J$

Wavelength corresponding to energy E can be calculated by using Planck's equation:

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

$\lambda =\frac{hc}{E}=\frac{6.626\times 10^{-34} Js\times 3\times 10^8 m/s}{9.176\times 10^{-20} J}=2.166\times 10^{-6} m=2166 nm$

The wavelength of the light emitted by a hydrogen atom for the given transition is 2166 nm.

8 0

3 years ago

When 2.35 g of potassium reacts with excess water, what mass of hydrogen gas is formed?

Butoxors [25]

Answer:

hope this is correct

7 0

3 years ago

Determine the volume of methane (ch 4 ) gas needed to react completely with 0.660 l of o 2 gas to form methanol (ch 3 oh).

Sloan [31]

Balance Chemical Equation for this reaction is,

2 CH₄ + O₂ → 2CH₃OH

According to this eq, 22.4 L (1 moles) of Oxygen requires 44.8 L (2 mole) CH₄ for complete reaction.
So, the volume of CH₄ required to consume 0.66 L of O₂ is calculated as,

22.4 L O₂ required to consume = 44.8 L CH₄
0.660 L O₂ will require = X L of CH₄

Solving for X,
X = (44.8 L × 0.660 L) ÷ 22.4 L

X = 1.320 L of CH₄

Result:
1.320 L of CH₄ <span>gas is needed to react completely with 0.660 L of O</span>₂<span> gas to form methanol (CH</span>₃OH<span>).</span>

4 0

3 years ago

If a solid has a density of 4.0 g/cm^3, what volume of the solid has a mass<br> of 24 g? Show work.

Mrrafil [7]

Answer:

<h2>Volume = 6 cm³</h2>

Explanation:

Density of a substance is given by

$Density = \frac{mass}{volume}$

From the question

Density = 4.0 g/cm³

mass = 24g

Substitute the values into the above formula and solve for the volume

That's

$4 = \frac{24}{v} \\4v = 24$

Divide both sides by 4

v = 6

We have the final answer as

<h3>Volume = 6 cm³</h3>

Hope this helps you

8 0

3 years ago