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slamgirl [31]
3 years ago
7

20 POINTS 2 QUESTIONS CAN YOU ANSWER THEM ???

Chemistry
2 answers:
Viktor [21]3 years ago
7 0
2. <span>1/8 = (1/2)³ </span>
<span>so it's 3 half lives.</span>
Reika [66]3 years ago
4 0

<u>Answer 1 :</u> The synthesis reaction is, N_2+3H_2\rightarrow 2NH_3

Explanation :

Synthesis reaction : It is a type of reaction in which the reactants present in elemental state react to give a single product.

(1) N_2+3H_2\rightarrow 2NH_3

This is a synthesis reaction.

(2) MgI_2+Br_2\rightarrow MgBr_2+I2

This is a single displacement reaction in which the most reactive element displaces the least reactive element.

(3) KClO_3\rightarrow KCl+O_2

This is a decomposition reaction in which larger reactant decomposes to give two or more products.

(4) HCl+NaOH\rightarrow NaCl+H_2O

This is a neutralization reaction in which an acid and a base react to give a salt and water as a product.

<u>Answer 2 : </u>The number of half-lives it take will be, 3

Formula used :

a=\frac{a_o}{2^n}

where,

a = amount of reactant left after n-half lives = \frac{1}{8}a_o

a_o = Initial amount of the reactant

n = number of half lives

Putting values in above equation, we get:

\frac{1}{8}a_o=\frac{a_o}{2^n}

2^n=8=2^3

n = 3

Therefore, the number of half-lives it take will be, 3

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3 years ago
In IR spectroscopy, we normally talk about "frequencies" when in reality we are referring to wavenumbers. What is the mathematic
Svetach [21]

Answer:

Here's what I get.

Explanation:

(b) Wavenumber and wavelength

The wavenumber is the distance over which a cycle repeats, that is, it is the number of waves in a unit distance.

\bar \nu = \dfrac{1}{\lambda}

Thus, if λ = 3 µm,

\bar \nu = \dfrac{1}{3 \times 10^{-6} \text{ m}}= 3.3 \times 10^{5}\text{ m}^{-1} = \textbf{3300 cm}^{-1}

(a) Wavenumber and frequency

Since

λ = c/f and 1/λ = f/c

the relation between wavenumber and frequency is

\bar \nu = \mathbf{\dfrac{f}{c}}

Thus, if f = 90 THz

\bar \nu = \dfrac{90 \times 10^{12} \text{ s}^{-1}}{3 \times 10^{8} \text{ m$\cdot$ s}^{-1}}= 3 \times 10^{5} \text{ m}^{-1} = \textbf{3000 cm}^{-1}

(c) Units

(i) Frequency

The units are s⁻¹ or Hz.

(ii) Wavelength

The SI base unit is metres, but infrared wavelengths are usually measured in micrometres (roughly 2.5 µm to 20 µm).

(iii) Wavenumber

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8 0
3 years ago
I need this ASAP i will give brainliest :)
shutvik [7]

Answer:

I really dont know i just guessed :(

Explanation:

5 0
3 years ago
PLEASE HELP ME<br><br> what would be the mass of 9.03 x 1021 molecules of hydrobromic acid (HBr)?
Nikitich [7]

We know 1 mole of any atom or molecules contains 6.033 \times 10^{23} atom or molecules.

1 mole of HBr i.e 81 gm/mol contains  6.033 \times 10^{23} atom or molecules.

So, mass of 9.03\times 10^{21} molecules is :

m=\dfrac{81\times 9.03\times 10^{21} }{6.033 \times 10^{23}}\\\\m= 1.21\ gm

Therefore, mass of  9.03\times 10^{21} molecules is 1.21 gm .

Hence, this is the required solution.

7 0
3 years ago
What will knowledge of chemistry enable you to do?
Fofino [41]
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