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3 years ago

Which of the following is true about a compound and its elements?

2 answers:

7 0

They can change properties completely
<span>They can be separated </span>
<span>They form a new set of elements and compounds </span>
<span>The elements become part of the original compounds</span>

Ahat [919]3 years ago

6 0

Answer:

The properties of a compound are different than the properties of its elements.

Explanation:

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Write the equation showing the formation of a monosubstituted product when butane reacts with chlorine. Use molecular formulas f

Harman [31]

Answer:

CH3CH2CH2CH3 + Cl2 --------> CH3CH2CH2CH2Cl + HCl

Explanation:

Alkanes react with halogens in the presence of light to yield alkyl halides. The degree of substitution increases as the reaction progresses. The reaction occurs by free radical mechanism.

The reaction between butane and chlorine molecule to yields a monosubstitution product occurs as follows;

CH3CH2CH2CH3 + Cl2 --------> CH3CH2CH2CH2Cl + HCl

4 0

3 years ago

Suppose that you add 24.3 g of an unknown molecular compound to 0.250 kg of benzene, which has a K f of 5.12 oC/m. With the adde

pochemuha

Solution :

We know that :

$\Delta T_f = k_f.m$ and $m=\frac{w_2}{m_2 \times w_1}$

Then, $\Delta T_f = k_f.\frac{w_2}{m_2.w_1}$ ..................(1)

Where,

$w_1$ = amount of solvent (in kg)

$w_2$ = amount of solute (in kg)

$m_2$ = molar mass of solute (g/mole)

$m$ = molality of solution (mole/kg)

Given :

$\Delta T_f$ = $3.14\ ^\circ C$ , $k_f= 5.12\ ^\circ C/m$

$=5.12 \ ^\circ C/mole/kg$

$=5.12 \ ^\circ C \ kg/mole$

$w_1$ = 0.250 kg, $w_2$ = 24.3 g

Then putting this values in the equation is (1),

$3.14 = \frac{5.12 \times 24.3}{m_2 \times 0.250}$

$m_2 = \frac{5.12 \times 24.3}{3.14 \times 0.250}$

$m_2= 158.49$ g/mole

So, the molar mass of the unknown compound is 158.49 g/mole.

7 0

3 years ago

Multiple choice-- please help!

kvasek [131]

The rate law for the reaction : r=k.[A]²

<h3>Further explanation</h3>

Given

Reaction

A ⟶ B + C

Required

The rate law

Solution

The rate law is a chemical equation that shows the relationship between reaction rate and the concentration / pressure of the reactants

For the second-order reaction it can be:

1. the square of the concentration of one reactant.

$\tt r=k[A]^2$

2. the product of the concentrations of two reactants.

$\tt r=k[A][B]$

And the reaction should be(for second order) :

2A ⟶ B + C

Thus, for reaction above (reactant consumption rate) :

$\tt r=-\dfrac{\Delta A}{2\Delta t}=k[A]^2$

6 0

3 years ago

What is the density of lithium metal (in g/cm3) if a cube measuring 0.82 cm × 1.45 cm × 1.25 cm has a mass of 0.794 g?

Maksim231197 [3]

Density is given by mass divided by the volume of a substance.
In this case the mass is 0.794 g and the volume is 0.82 cm ×1.45 cm ×1.25 cm = 1.48625 cm³.
Therefore, density = 0.794/ 1.48625
= 0.5342 g/cm³
Thus, the density of lithium metal is 0.5342 g/cm³

7 0

4 years ago

Read 2 more answers

Having done the experiment, explain briefly how the mass of zinc not equal the mass of lead gained (hint: the periodic table)

masya89 [10]

Answer:

Due to the difference in the relative atomic masses and therefore, the molecular masses of Zn and Pb, one mole of Zn is about 3.2 times lighter than one mole of Pb

Explanation:

From the periodic table, we have;

The atomic number of zinc, Zn = 30

The atomic mass of zinc, Zn = 65.38 amu

The molar mass of zinc, Zn = 65.38 g/mol

The atomic number of lead, Pb = 82

The atomic mass of lead, Pb = 207.2 amu

The molar mass of lead, Pb = 207.2 g/mol

Therefore, whereby equal number of moles of Zn is lost and Pb is gained, we have;

Mass of 1 mole of Zn = 65.38 grams

Therefore, 1 gram of Zn = 1/65.38 moles = 0.0153 moles

0.12 grams of Zn = 0.12×0.0153 = 0.00184 moles of Zn

Given that equal number of moles of Zn and Pb are involved in the reaction, the number of moles of Pb gained = 0.00184 moles

The mass of Pb gained = Number of moles of Pb gained × Molar mass of Pb

The mass of Pb gained = 0.00184 × 207.2 = 0.38 g ≈ 0.4 g.

Amount of Pb gained = 0.43 g ≈ 0.4 g

4 0

3 years ago