Question

please answer all, and type please

Problems and questions (show all calculations, correct significant figures and units) 1. Why is it important to test the crucible for cracks before heating it? 2. Write the correct balanced equation for the dehydration (removal of water) of the magnesium sulfate hydrate obtained in Procedure B of this experiment. 3. How many moles are in 70.0 grams of potassium hydroxide? 4. A compound is formed when 0.300 moles of barium combine with 0.600 moles of chlorine. What is the empirical formula for this compound? 5. A compound contains 3.24 grams of sodium, 2.26 grams of sulfur, and 4.51 grams of oxygen. What is the empirical formula for this compound? 6. Calculate the percent water in iron(II) sulfate heptahydrate.

Answer 1

Following is the - complete Answer -&- Explanation: for the first four questions ( i.e. Q.1  to Q.4 ), of the given: Question Set... in....typed format...

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$\Rightarrow$Question - ( 1 ):

$\Rightarrow$Answer:

It is important, because, if the crucible : is not checked: for  cracks: before further heating: the crucible, may crack further, upon heating, which may lead to the leakage and loss,of the substance or compound, placed on the crucible...

$\Rightarrow$Explanation:

Even if a crucible: has a very small crack : on its surface, further heating, may cause the crucible: to break. And, in that case, the substance / compound: taken in the crucible: for testing, will be lost: and after breakage, the crucible: will be needed to be changed and the : chemical testing in the laboratory: will have to be started, again... In order to avoid the above: scenario/ condition: a crucible must always be checked for cracks, before further heating.

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$\Rightarrow$Question - ( 2 ):

$\Rightarrow$Answer:

balanced chemical equation: MgSO₄. 7H₂O (s)   $\rightleftharpoons$ MgSO₄ (s) + 7 H₂O (l)

$\Rightarrow$Explanation:

Following is the complete Explanation: for the above Answer.

• Step - 1:

We know the following chemical formula: of the given compounds:

1. MgSO₄. 7H₂O :   Magnesium sulfate hepta-hydrate OR epsom salt
2. MgSO₄. :   Magnesium sulfate anhydrous

• ​​​​​​​Step - 2:

​​​​​​​Since, upon heating: Magnesium sulfate heptahydrate, will lose the water of hydration: attached with the molecule, i.e. the hydrate, it will become : dehydrated, and will become the anhydrous form; i.e. anhydrous magnesium sulfate...

• Step - 3:

​​​​​​​Thus, following will be the balanced chemical equation: for dehydration : of Magnesium sulfate heptahydrate ( i.e. MgSO₄ . 7H₂O )

$\Rightarrow$MgSO₄. 7H₂O (s)   $\rightleftharpoons$ MgSO₄ (s) + 7 H₂O (l) ----------------------- ( Answer )

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$\Rightarrow$Question - ( 3 ):

$\Rightarrow$Answer:

Number of moles of potassium hydroxide ( KOH ) = 1.248 mol ( moles KOH ; approx. )

$\Rightarrow$Explanation:

Following is the complete Explanation: for the above: Answer.

• Given:

1. ​​​​​​​ Mass of KOH = 70.0 g ( grams )
2. We know: the molar mass of KOH = 56.10 g/mol

• ​​​​​​​Step - 1:

​​​​​​​Therefore: the number of moles of KOH, can be determined, as the following:

$\Rightarrow$Number of moles of KOH = ( mass of KOH ) / ( molar mass of KOH ) = ( 70.0 g ) / ( 56.10 g/mol )

= 1.248 mol ( moles of KOH )  

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$\Rightarrow$Question - ( 4 ):

$\Rightarrow$Answer:

Empirical formula of the compound, is:   BaCl₂   

$\Rightarrow$Explanation:

Following is the complete Explanation: for the above Answer.

• Given:

​​​​​​​We are given with the following:

1. Number of moles of Barium ( Ba ) : = 0.300 mol
2. Number of moles of Chlorine ( Cl ) : =  0.600 mol
3. Molar ratio: Ba : Cl = 1 : 2

• ​​​​​​​Step - 1:

​​​​​​​Therefore: from the above information: we can surely say the following:

i.e. $\Rightarrow$ One ( 1 ) mole of Barium ( Ba) , will get attached with two ( 2 ) moles of Chlorine ( Cl ) , and will form the molecule: as : BaCl₂  , i.e. Barium Chloride, will be formed...

Therefore:

$\Rightarrow$ Empirical formula will be: BaCl₂...

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