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2 years ago

10

Connie was making sodium chloride by adding an acid to an alkali. She followed the progress of the reaction with a pH sensor. At

which pH would she know that the acid and alkali had completely reacted to give a salt solution?

1 answer:

Misha Larkins [42]2 years ago

5 0

⇒Answer:

When the pH sensor hits pH=7.

⇒Explanation:

Because pH=7 is the indicator that the acid and alkali have been neutralized.

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calculate the mass of calcium phosphate and the mass of sodium chloride that could be formed when a solution containing 12.00g o

Leviafan [203]

Answer : The mass of calcium phosphate and the mass of sodium chloride that formed could be, 9.3 and 10.5 grams respectively.

Explanation : Given,

Mass of $Na_3PO_4$ = 12.00 g

Mass of $CaCl_2$ = 10.0 g

Molar mass of $Na_3PO_4$ = 164 g/mol

Molar mass of $CaCl_2$ = 111 g/mol

Molar mass of $NaCl$ = 58.5 g/mol

Molar mass of $Ca_3(PO_4)_2$ = 310 g/mol

First we have to calculate the moles of $Na_3PO_4$ and $CaCl_2$ .

$\text{Moles of }Na_3PO_4=\frac{\text{Given mass }Na_3PO_4}{\text{Molar mass }Na_3PO_4}$

$\text{Moles of }Na_3PO_4=\frac{12.00g}{164g/mol}=0.0732mol$

and,

$\text{Moles of }CaCl_2=\frac{\text{Given mass }CaCl_2}{\text{Molar mass }CaCl_2}$

$\text{Moles of }CaCl_2=\frac{10.0g}{111g/mol}=0.0901mol$

Now we have to calculate the limiting and excess reagent.

The balanced chemical reaction is:

$2Na_3PO_4+3CaCl_2\rightarrow 6NaCl+Ca_3(PO_4)_2$

From the balanced reaction we conclude that

As, 3 mole of $CaCl_2$ react with 2 mole of $Na_3PO_4$

So, 0.0901 moles of $CaCl_2$ react with $\frac{2}{3}\times 0.0901=0.0601$ moles of $Na_3PO_4$

From this we conclude that, $Na_3PO_4$ is an excess reagent because the given moles are greater than the required moles and $CaCl_2$ is a limiting reagent and it limits the formation of product.

Now we have to calculate the moles of $NaCl$ and $Ca_3(PO_4)_2$

From the reaction, we conclude that

As, 3 mole of $CaCl_2$ react to give 6 mole of $NaCl$

So, 0.0901 mole of $CaCl_2$ react to give $\frac{6}{3}\times 0.0901=0.1802$ mole of $NaCl$

and,

As, 3 mole of $CaCl_2$ react to give 1 mole of $Ca_3(PO_4)_2$

So, 0.0901 mole of $CaCl_2$ react to give $\frac{1}{3}\times 0.0901=0.030$ mole of $Ca_3(PO_4)_2$

Now we have to calculate the mass of $NaCl$ and $Ca_3(PO_4)_2$

$\text{ Mass of }NaCl=\text{ Moles of }NaCl\times \text{ Molar mass of }NaCl$

$\text{ Mass of }NaCl=(0.1802moles)\times (58.5g/mole)=10.5g$

and,

$\text{ Mass of }Ca_3(PO_4)_2=\text{ Moles of }Ca_3(PO_4)_2\times \text{ Molar mass of }Ca_3(PO_4)_2$

$\text{ Mass of }Ca_3(PO_4)_2=(0.030moles)\times (310g/mole)=9.3g$

Therefore, the mass of calcium phosphate and the mass of sodium chloride that formed could be, 9.3 and 10.5 grams respectively.

5 0

3 years ago

A solid rubber ball with a mass of 5.9 grams sank in water. A hollow rubber ball with the same mass floats in water. Explain why

Stells [14]

Answer:

The hollow ball is more buoyant than the solid ball.

Explanation:

The hollow ball will float while the solid ball sinks because the volume of water displaced by the hollow ball is more than that displaced by the solid ball.

An object floats when it displaces a volume of water equal to its weight. A solid ball is more compact, and hence, does not displace a lot of water when dropped into a bowl full of water. On the other hand, the hollow ball will have a larger curved surface area, since it has no fill. This will make it displace a larger volume of water and hence make it float.

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3 years ago

What is dynamic equilibrium? What is dynamic equilibrium? Dynamic equilibrium in a chemical reaction is the condition in which t

OverLord2011 [107]

Answer:

The correct answer is: Dynamic equilibrium in a chemical reaction is the condition in which the rate of the forward reaction equals the rate of the reverse reaction.

Explanation:

Dynamic equilibrium is a chemical equilibrium between froward reaction and backward or reverse reaction where rate of reaction going forwards is equal to the rate of reaction going backward (reverse).

Some other properties of dynamic equilibrium are:

Chemical equilibrium are attained is closed system.
The macroscopic remains constant like: volume, pressure, energy etc.
The concentration of the reactants and products remain constant.They are not always equal.

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3 years ago

How long would it take for 1.50 mol of water at 100.0 ∘c to be converted completely into steam if heat were added at a constant

Aleksandr-060686 [28]

To determine the time it takes to completely vaporize the given amount of water, we first determine the total heat that is being absorbed from the process. To do this, we need information on the latent heat of vaporization of water. This heat is being absorbed by the process of phase change without any change in the temperature of the system. For water, it is equal to 40.8 kJ / mol.

Total heat = 40.8 kJ / mol ( 1.50 mol ) = 61.2 kJ of heat is to be absorbed

Given the constant rate of 19.0 J/s supply of energy to the system, we determine the time as follows:

Time = 61.2 kJ ( 1000 J / 1 kJ ) / 19.0 J/s = 3221.05 s

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3 years ago

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What product of the krebs cycle is considered a waste product of the reaction?

Rufina [12.5K]

The answer is carbon dioxide

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3 years ago