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3 years ago

Help i just need people to answer the question today

Chemistry

1 answer:

yKpoI14uk [10]3 years ago

6 0

Answer:

1) Hydrogen

2) Methane

3) Carbon

4) Structural isomer

5) Ethene also known as ethylene

6) Hydrocarbons are widely used as fuel

7) Crude oil

Explanation:

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The conversion of methyl isonitrile to acetonitrile in the gas phase at 250 °C CH3CN(g) is first order in CH3NC with a rate cons

nadya68 [22]

Answer: The concentration of $CH_3NC$ will be $1.56\times 10^{-2}M$ after 416 seconds have passed.

Explanation:

Expression for rate law for first order kinetics is given by:

$t=\frac{2.303}{k}\log\frac{a}{a-x}$

where,

k = rate constant = $3.00\times 10^{-3}s^{-1}$

t = age of sample = ?

a = let initial amount of the reactant = $5.45\times 10^{-2}M$

a - x = amount left after decay process = $1.56\times 10^{-2}M$

$t=\frac{2.303}{3.00\times 10^{-3}}\log\frac{5.45\times 10^{-2}}{1.56\times 10^{-2}}$

$t=416s$

The concentration of $CH_3NC$ will be $1.56\times 10^{-2}M$ after 416 seconds have passed.

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3 years ago

the atomic masses of 63 cu (69.17 percent) and 65 cu (30.83 percent) are 62.94 and 64.93 amu, respectively. calculate the averag

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Answer:

The average atomic mass of copper is 63.55 amu.

Explanation:

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2 years ago

You have 125 g of a certain seasoning and are told that it contains 70.0 g of salt. What is the peroentage of salt by mass in th

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$\frac{70}{125} \times 100 = 56\%$

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3 years ago

Read 2 more answers

Magnesium has three naturally occurring isotopes, ²⁴Mg (isotopic mass = 23.9850 amu, abundance = 78.99%), ²⁵Mg (isotopic mass =

joja [24]

The atomic mass of the magnesium is : 24.31⋅g.

<h3>What is isotopes?</h3>

Isotopes are members of a family of elements that all have the same number of protons and different numbers of neutrons. The number of protons in the nucleus determines the atomic number of an element on the periodic table.

Magnesium has three natural isotopes: ²⁴Mg, ²⁵Mg, and ²⁶Mg.

<h3>What is atomic mass ?</h3>

Atomic mass is the mass of an atom. The SI unit of mass is the kilogram, while atomic mass is often expressed in the non-SI unit dalton (synonymous with uniform atomic mass unit). 1 Da is defined as 1/12 the mass of a free carbon-12 atom at rest in the ground state.

Calculation :

The atomic mass is the weighted average of the individual isotopic masses:

(23.99×78.99%+24.99×10.00%+25.98×11.01%)⋅g=24.31⋅g

To know more atomic mass please click here : brainly.com/question/338808

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4 0

1 year ago

A compound is 42.9% C, 2.4% H, 16.7% N, and 38.1% O, by mass. Addition of 6.45 g of this compound to 50.0 mL benzene, lowers the

Romashka [77]

This is an incomplete question, here is a complete question.

A compound is 42.9% C, 2.4% H, 16.7% N and 38.1% O by mass. Addition of 6.45 g of this compound to 50.0 mL benzene, C₆H₆ (d= 0.879 g/mL; Kf= 5.12 degrees Celsius/m), lowers the freezing point from 5.53 to 1.37 degrees Celsius. What is the molecular formula of this compound?

Answer : The molecular of the compound is, $C_6H_4N_2O_4$

Explanation :

First we have to calculate the mass of benzene.

$\text{Mass of benzene}=\text{Density of benzene}\times \text{Volume of benzene}$

$\text{Mass of benzene}=0.879g/mL\times 50.0mL=43.95g$

Now we have to calculate the molar mass of unknown compound.

Given:

Mass of unknown compound (solute) = 6.45 g

Mass of benzene (solvent) = 43.95 g = 0.04395 kg

Formula used :

$\Delta T_f=K_f\times m\\\\\Delta T_f=K_f\times\frac{\text{Mass of unknown compound}}{\text{Molar mass of unknown compound}\times \text{Mass of benzene in Kg}}$

where,

$\Delta T_f$ = change in freezing point = $5.53-1.37=4.16^oC$

$\Delta T_s$ = freezing point of solution

$\Delta T^o$ = freezing point of benzene

Molal-freezing-point-depression constant $(K_f)$ for benzene = $5.12^oC/m$

m = molality

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

$4.16^oC=(5.12^oC/m)\times \frac{6.45g}{\text{Molar mass of unknown compound}\times 0.04395kg}$

$\text{Molar mass of unknown compound}=180.6g/mol$

If percentage are given then we are taking total mass is 100 grams.

So, the mass of each element is equal to the percentage given.

Mass of C = 42.9 g

Mass of H = 2.4 g

Mass of N = 16.7 g

Mass of O = 38.1 g

Molar mass of C = 12 g/mole

Molar mass of H = 1 g/mole

Molar mass of N = 14 g/mole

Molar mass of O = 16 g/mole

Step 1 : convert given masses into moles.

Moles of C = $\frac{\text{ given mass of C}}{\text{ molar mass of C}}= \frac{42.9g}{12g/mole}=3.575moles$

Moles of H = $\frac{\text{ given mass of H}}{\text{ molar mass of H}}= \frac{2.4g}{1g/mole}=2.4moles$

Moles of N = $\frac{\text{ given mass of N}}{\text{ molar mass of N}}= \frac{16.7g}{14g/mole}=1.193moles$

Moles of O = $\frac{\text{ given mass of O}}{\text{ molar mass of O}}= \frac{38.1g}{16g/mole}=2.381moles$

Step 2 : For the mole ratio, divide each value of moles by the smallest number of moles calculated.

For C = $\frac{3.575}{1.193}=2.99\approx 3$

For H = $\frac{2.4}{1.193}=2.01\approx 2$

For N = $\frac{1.193}{1.193}=1$

For O = $\frac{2.381}{1.193}=1.99\approx 2$

The ratio of C : H : N : O = 3 : 2 : 1 : 2

The mole ratio of the element is represented by subscripts in empirical formula.

The Empirical formula = $C_3H_2N_1O_2$

The empirical formula weight = 3(12) + 2(1) + 1(14) + 2(16) = 84 gram/eq

Now we have to calculate the molecular formula of the compound.

Formula used :

$n=\frac{\text{Molecular formula}}{\text{Empirical formula weight}}$

$n=\frac{180.6}{84}=2$

Molecular formula = $(C_3H_2N_1O_2)_n=(C_3H_2N_1O_2)_2=C_6H_4N_2O_4$

Therefore, the molecular of the compound is, $C_6H_4N_2O_4$

3 0

3 years ago