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Lerok [7]
3 years ago
14

Suppose you were making 100.0 mL of a solution that is 0.040 M KCl. What mass of KCl should you weigh to make this solution?

Chemistry
1 answer:
scZoUnD [109]3 years ago
3 0

Answer:

mass = 0.2982 grams

Explanation:

Given that;

volume = 100.0 mL = 0.1 L

Molarity =0.040 M

Since Molarity = \frac{no of moles }{volume}

0.040 M = \frac{x}{0.1}

(x) no of moles = 0.040 × 0.1

= 0.004 moles

Also; to calculate the  mass of KCl should you weigh to make this solution;

we have;

no of moles =\frac{mass}{molar mass}

molar mass of KCl = 74.55 g/mol

∴

0.004 moles = \frac{mass}{74.55g/mol}

mass = 0.004 moles * 74.55 \frac{g}{mol}

mass = 0.2982 grams

Hence, the mass of KCl should you weigh to make this solution is  0.2982 grams

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Answer:

A. Cu^+2(aq)cathode ---> Cu^+2(aq)anode

Explanation:

Electrolysis is the process in which current is passed through a solution thereby causing a chemical change at the anode and cathode. Copper is being purified using electrolysis by using impure copper at the anode and pure copper at the cathode. This pure and impure copper are placed in a copper(ii)sulfate electrolyte solution and dc current is made to pass through it.  The resulting changes at the anode and cathode are given by the equation:

cathode: Cu²⁺  + 2e⁻    ⇒     Cu

anode:    Cu     ⇒       Cu²⁺  + 2e⁻

3 0
3 years ago
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A solid is 5 cm tall, 3 am wide, and 2 cm thick. It has a mass of 135 g. What is the solid's density?
gizmo_the_mogwai [7]

<u>Answer:</u>

density of solid = 4.5 g/cm³

<u>Explanation:</u>

density = mass ÷ volume

• We know the mass of the object (135 g). We need to calculate the volume:

Volume = length × width × thickness

             = 5 cm × 3 cm × 2 cm

             = 30 cm³

• Now we can calculate the solid's density:

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What must molecules do to react?
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28. What is the heat of reaction for the forward reaction?
ValentinkaMS [17]

Answer:

Check Explanation

Explanation:

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ΔH°run = H°(products) - H°(reactants)

When the heat of reaction is negative, the reaction is said to be exothermic and when it is positive, the reaction is said to be endothermic.

Hope this Helps!!!

8 0
3 years ago
A student is asked to make 500 mL of a buffer solution for an upcoming laboratory investigation that requires 50.0 mL of 3.0 M p
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To solve this we use the equation, 

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Hope this answers the question. Have a nice day.

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