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3 years ago

Which substance can not be broken down by a

Chemistry

1 answer:

Tomtit [17]3 years ago

7 0

Answer: (3) silicon

Explanation:

Element is a pure substance which is composed of atoms of similar elements.It can not be decomposed into simpler constituents using chemical reactions.Example: Silicon (Si)

Compound is a pure substance which is made from atoms of different elements combined together in a fixed ratio by mass.It can be decomposed into simpler constituents using chemical reactions. Example: ethane $(C_2H_6)$ , propanone $(CH_3COCH_3)$ and water $(H_2O)$

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Identify the conjugate base in each pairs

DiKsa [7]

Answer: 1) $RCOO^-$

2) $H_2PO_4^-$

3) $RNH_2$

4) $HCO_3^-$

Explanation:

According to the Bronsted-Lowry conjugate acid-base theory, an acid is defined as a substance which looses donates protons and thus forming conjugate base and a base is defined as a substance which accepts protons and thus forming conjugate acid.

1) $RCOOH\rightarrow RCOO^-+H^+$

Here, $RCOOH$ is loosing a proton, thus it is considered as an acid and after losing a proton, it forms $RCOO^-$ which is a conjugate base.

2) $H_3PO_4\rightarrow H_2PO_4^-+H^+$

Here, $H_3PO_4$ is loosing a proton, thus it is considered as an acid and after losing a proton, it forms $H_2PO_4^-$ which is a conjugate base.

3) $RNH_3^+\rightarrow RNH_2+H^+$

Here, $RNH_3^+$ is loosing a proton, thus it is considered as an acid and after losing a proton, it forms $RNH_2$ which is a conjugate base.

4) $H_2CO_3\rightarrow HCO_3^-+H^+$

Here, $H_2CO_3$ is loosing a proton, thus it is considered as an acid and after losing a proton, it forms $HCO_3^-$ which is a conjugate base.

8 0

2 years ago

Calculate the number of moles of Cl2 produced at equilibrium when 3.98 mol of PCl5 is heated at 283.9 deg celsius in a vessel ha

ddd [48]

Answer:

1.274 moles

Explanation:

The equation for the reaction can be represented as follows:

$PCl_5(g)$ ⇄ $PCl_3(g)$ + $Cl_2(g)$

K = 0.060

K = $\frac{[PCl_3][Cl_2]}{[PCl_5]}$

Concentration of $PCl_5(g)$ = $\frac{numbers of moles}{volume}$

Concentration of $PCl_5(g)$ = $\frac{3.98}{10.0}$

Concentration of $PCl_5(g)$ = 0.398 moles

If we construct an ICE table for the above equation; we have:

$PCl_5(g)$ ⇄ $PCl_3(g)$ + $Cl_2(g)$

Initial 0.398 0 0

Change - x + x + x

Equilibrium (0.398 - x) x x

K = $\frac{[PCl_3][Cl_2]}{[PCl_5]}$

K = $\frac{[x][x]}{[0.398-x]}$

K = $\frac{x^2}{0.398-x}$

0.060 = $\frac{x^2}{0.398-x}$

0.06(0.398-x) = x²

0.02388 - 0.060x = x²

x² + 0.060x - 0.02388 = 0 (quadratic equation)

a = 1; b= 0.06; c= -0.02388

Using quadratic formula;

= $\frac{-b+/-\sqrt{b^2-4ac} }{2a}$

= $\frac{-0.06+/-\sqrt{(0.06)^2-4(1)(-0.02388)} }{(2*1)}$

= $\frac{-0.060+/-\sqrt{0.0036+0.09552} }{2}$

= $\frac{-0.06+/-\sqrt{0.09912} }{2}$

= $\frac{-0.06+/-0.3148}{2}$

= $\frac{-0.060+0.3148}{2}$ or $\frac{-0.060-0.3148}{2}$

= $\frac{0.2548}{2}$ or $\frac{-0.3748}{2}$

= 0.1274 or -0.1874

We go by the positive value which says:

[x] = 0.1274 M

number of moles = 0.1274 × 10.0

= 1.274 moles

∴ the number of moles of Cl₂ produced at equilibrium = 1.274 moles

7 0

3 years ago

Explain how they would make solutions of the sulfuric acid at five different concentrations

katrin2010 [14]

The sulfuric acid can be constituted into different concentrations using distilled water as a diluent.

<h3>What is dilution of acid?</h3>

Dilution of acid is defined as the decrease in the concentration of an acid using water.

For sulfuric acid to be diluted, it is slowly added to distilled water using the following guidelines:

Add 150 ml of water to the beaker and add the desired amount of acid. This will give a diluted concentration of the given acid.

Learn more about acid here:

brainly.com/question/25148363

#SPJ1

3 0

1 year ago

How do an ionic bond and a covalent bond differ

storchak [24]

An ionic bond is the transfer of electrons and a covalent bond is a sharing of electrons

Happy studying! ^_^

7 0

2 years ago

A race car is driven by a professional driver at 99 . What is this speed in and ? 1 mile = 1.61 kilometers 1 hour = 60 minutes E

slavikrds [6]

Answer: The speed is equivalent to 159.39 kilometers per hour or 2.65 kilometers per minute.

Explanation:

Given, The speed of a race car = 99 miles/ hour

To convert the speed into kilometers per hour and kilometers per minute

Since 1 mile = 1.61 kilometers

So, Speed of car = (99 ) x (1.61 )

= 159.39 kilometers per hour.

Also, 1 hour = 60 minutes

Then, Speed of car = (159.39) ÷60

= 2.6565≈2.65 kilometer per minute.

Hence, the speed is equivalent to 159.39 kilometers per hour or 2.65 kilometers per minute.

4 0

3 years ago