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3 years ago

Calculate the percentage of water of crystallisation in MgSO⁴ 7H²O

Chemistry

2 answers:

Bas_tet [7]3 years ago

7 0

Answer:

Formula of EPSOM salt = MgSO4.7H2O

molecular mass of MgSO4.7H2O = atomic mass of Mg + atomic mass of S + 4 × atomic mass of O + 7 { 2 × atomic mass of H + atomic mass of O }

= 24 + 32 + 4× 16 + 7{ 2 × 1 + 16 } g/mol

= (24 + 32 + 64+ 126 ) g/mol

= 246 g/mol

molecular mass of total water = 7 × ( 2× atomic mass of H + atomic mass of O )

= 7 × 18 = 126 g/mol

now ,

% mass of H2O in EPSOM salt = {total molar mass of H2O/molar mass of Epsom salts }× 100

= {126/246 } × 100

= 12600/246

= 51.21 %

Explanation:

i have done it hope it helps

lyudmila [28]3 years ago

6 0

I think that to my calculations it should equal to 51.20 I am not sure but I tried x

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Argon has a pressure of 34.6 atm. It is transferred to a new tank with a volume of 456 L and pressure of 2.94 atm. What was the

NemiM [27]

Answer:

38.75 L

Explanation:

From the question,

Applying Boyles Law,

PV = P'V'....................... Equation 1

Where P = Original pressure of the Argon gas, V = Original Volume of Argon gas, P' = Final pressure of Argon gas, V' = Final Volume of Argon gas.

make V the subject of the equation

V = P'V'/P.................... Equation 2

Given: P = 34.6 atm, V' = 456 L, P' = 2.94 atm.

Substitute these values into equation 2

V = (456×2.94)/34.6

V = 38.75 L

3 0

3 years ago

Calculate the ph at of a solution of sodium hypochlorite . note that hypochlorous acid is a weak acid with a of . round your ans

loris [4]

The question is incomplete, here is the complete question:

Calculate the pH at 25°C of a 0.39 M solution of sodium hypochlorite NaClO. Note that hypochlorous acid HClO is a weak acid with a pKa of 7.50. Round your answer to 1 decimal place.

Answer: The pH of the solution is 10.4

Explanation:

We are given:

Molarity of sodium hypochlorite = 0.39 M

$pK_a$ of HClO = 7.50

We know that:

$pK_a=-\log K_a$

$K_a$ of HClO = $10^{-7.50}=3.16\times 10^{-8}$

To calculate the base dissociation constant for the given acid dissociation constant, we use the equation:

$K_w=K_b\times K_a$

where,

$K_w$ = Ionic product of water = $10^{-14}$

$K_a$ = Acid dissociation constant = $3.16\times 10^{-8}$

$K_b$ = Base dissociation constant

Putting values in above equation, we get:

$10^{-14}=3.16\times 10^{-8}\times K_b\\\\K_b=\frac{10^{-14}}{3.16\times 10^{-8}}=3.16\times 10^{-7}$

The chemical equation for the reaction of hypochlorite ion with water follows:

$ClO^-+H_2O\rightarrow HClO+OH^-$

Initial: 0.39

At eqllm: 0.39-x x x

The expression of $K_b$ for above equation follows:

$K_b=\frac{[HClO][OH^-]}{[ClO^-]}$

Putting values in above equation, we get:

$3.16\times 10^{-7}=\frac{x\times x}{(0.39-x)}\\\\x=-0.00035,0.00035$

Neglecting the negative value of 'x' because concentration cannot be negative

To calculate the pOH of the solution, we use the equation:

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

We are given:

$[OH^-]=0.00035M$

Putting values in above equation, we get:

$pOH=-\log (0.00035)=3.6$

To calculate pH of the solution, we use the equation:

$pH+pOH=14\\pH=14-3.6=10.4$

Hence, the pH of the solution is 10.4

3 0

3 years ago

Wha is boiling point

Troyanec [42]

The boiling point is the temperature at which the vapor pressure of a liquid equals the external pressure surrounding the liquid. Therefore, the boiling point of a liquid depends on atmospheric pressure.

7 0

3 years ago

Which ionic equation describes a redox reaction? A. Ag(+) + Cl- = AgCl B. 2H(+) + CO3(2-) = CO2 + H2O C. H(+) + OH(-) = H2O D. Z

Gennadij [26K]

Answer: The correct option is D. $Zn+Cu^{2+}\rightarrow Zn^{2+}+Cu$

Explanation:

Redox reaction is defined as the reaction in which oxidation and reduction take place simultaneously. It is known as the reaction in which the exchange of electrons takes place.

The oxidation reaction is defined as the reaction in which a chemical species loses electrons in a chemical reaction. It occurs when the oxidation number of a species increases.

A reduction reaction is defined as the reaction in which a chemical species gains electrons in a chemical reaction. It occurs when the oxidation number of a species decreases.

From the given ionic reactions:

$Zn+Cu^{2+}\rightarrow Zn^{2+}+Cu$

On the reactant side:

Oxidation number of Zn = 0

Oxidation number of Cu = +2

On the product side:

Oxidation number of Cu = 0

Oxidation number of Zn = +2

As the oxidation number of Zn is increasing from 0 to +2. Thus, it is getting oxidized. Similarly, the oxidation number of Cu is decreasing from +2 to 0. Thus, it is getting reduced. Therefore, forming a redox couple

Hence, the correct option is D. $Zn+Cu^{2+}\rightarrow Zn^{2+}+Cu$

6 0

3 years ago

9.0 mol Na2S can from 9.0 mol CuS and 8.0 mol CuSO4 can form 8.0 mol Cus.

ICE Princess25 [194]

Answer:

765.0 grams CuS

Explanation:

The limiting reagent is the reactant which completely reacts before the other reactant(s) is used up. When 9.0 moles Na₂S and 8.0 moles CuSO₄ react, it appears that CuSO₄ is the limiting reagent. You can tell because it results in the production of less product.

You can determine the mass of CuS by multiplying the moles by the molar mass. It is important to arrange the ratio in a way that allows for the cancellation of units.

Molar Mass (CuS): 95.62 g/mol

8.0 moles CuS 95.62 g
------------------------- x ----------------------- = 765.0 grams CuS
1 mole

4 0

2 years ago