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3 years ago

How can melting point and boiling point identify a substance

Chemistry

1 answer:

Nikolay [14]3 years ago

8 0

Answer:

to determine of it is a solid liquid or gas.

Explanation:

The melting point is the temperature at which a substance converts from a solid state to a liquid state.

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The period of daylight experienced each day on every part of Earth would be shorter if which one of the following changes occurr

lilavasa [31]

Answer:

Explanation:

5 0

3 years ago

Calculate the acid dissociation constant Ka of a 0.2 M solution of weak acid that is 0.1% ionized is ________.

mars1129 [50]

Answer: acid dissociation constant Ka= 2.00×10^-7

Explanation:

For the reaction

HA + H20. ----> H3O+ A-

Initially: C. 0. 0

After : C-Cx. Cx. Cx

Ka= [H3O+][A-]/[HA]

Ka= Cx × Cx/C-Cx

Ka= C²X²/C(1-x)

Ka= Cx²/1-x

Where x is degree of dissociation = 0.1% = 0.001 and c is the concentration =0.2

Ka= 0.2(0.001²)/(1-0.001)

Ka= 2.00×10^-7

Therefore the dissociation constant is

2.00×10^-7

7 0

3 years ago

An important reaction that takes place in a blast furnace during the production of iron is the formation of iron metal and CO2 f

ladessa [460]

Answer: Mass of $Fe_2O_3$ required to form 930 kg of iron is 1328 kg

Explanation:

To calculate the number of moles, we use the equation:

$\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}$ .....(1)

For iron:

Given mass of iron = 930 kg = 930000 g (1kg=1000g)

Molar mass of iron = 56 g/mol

Putting values in equation 1, we get:

$\text{Moles of iron}=\frac{930000g}{56g/mol}=16607mol$

The chemical equation for the production of iron follows:

$Fe_2O_3+3CO\rightarrow 2Fe+3CO_2$

By Stoichiometry of the reaction:

2 moles of iron are produced by = 1 mole of $Fe_2O_3$

So, 16607 moles of iron will be produced by = $\frac{1}{2}\times 16607=8303moles$ of $Fe_2O_3$

Now, calculating the mass of $Fe_2O_3$ from equation 1, we get:

Mass of $Fe_2O_3$ = $moles\times {\text {molar mass}}=8303\times 160=1328480g=1328kg$

Thus mass of $Fe_2O_3$ required to form 930 kg of iron is 1328 kg

6 0

3 years ago

Calcium hydroxide is a strong base but is not very soluble ( Ksp = 5.02 X 10-6 ). What is the pH of a saturated solution of Ca(O

Misha Larkins [42]

Answer : The pH of a saturated solution is, 12.33

Explanation : Given,

$K_{sp}$ = $5.02\times 10^{-6}$

First we have to calculate the solubility of $OH^-$ ion.

The balanced equilibrium reaction will be:

$Ca(OH)_2\rightleftharpoons Ca^{2+}+2OH^-$

Let the solubility will be, 's'.

The concentration of $Ca^{2+}$ ion = s

The concentration of $OH^-$ ion = 2s

The expression for solubility constant for this reaction will be,

$K_{sp}=[Ca^{2+}][OH^-]^2$

Let the solubility will be, 's'

$K_{sp}=(s)\times (2s)^2$

$K_{sp}=(4s)^3$

Now put the value of $K_[sp}$ in this expression, we get the solubility.

$5.02\times 10^{-6}=(4s)^3$

$s=1.079\times 10^{-2}M$

The concentration of $Ca^{2+}$ ion = s = $1.079\times 10^{-2}M$

The concentration of $OH^-$ ion = 2s = $2\times (1.079\times 10^{-2}M)=2.158\times 10^{-2}M$

First we have to calculate the pOH.

$pOH=-\log [OH^-]$

$pOH=-\log (2.158\times 10^{-2})$

$pOH=1.67$

Now we have to calculate the pH.

$pH+pOH=14\\\\pH=14-pOH\\\\pH=14-1.67=12.33$

Therefore, the pH of a saturated solution is, 12.33

7 0

3 years ago

Can someone provide a answer with explanation for this question? Thanks!

zhuklara [117]

Answer:

Explanation:

4 0

1 year ago