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3 years ago

Please I need help on these 3 questions. Thank You.

Chemistry

1 answer:

Liula [17]3 years ago

6 0

V = 200 mL (volume)

c = 3 M = 3 mol/L (concentration)

First we convert mL to L:

200 mL = 0.2 L

Then we calculate the moles using the formula: n = V × c = 0.2 L × 3 mol = 0.6 mol

Finally, we just use the molar mass of CaF2 to calculate the actual mass:

molar mass = 78 g/mol

The formula is: m = n × mm (mass = moles × molar mass)

m = 0.6 mol × 78 g/mol = 46.8 g

For this question the steps are exactly like the first question.

V = 50mL = 0.05 L

c = 12 M = 12 mol/L

n = V × c = 0.05 L × 12 mol/L = 0.6 mol

molar mass (HCl) = 36.5 g/mol

m = n × mm = 0.6 mol × 36.5 g/mol = 21.9 g.

The steps for this question are the opposite way.

m(K2CO3) = 250 g

molar mass = 138 g/mol

n = m ÷ mm = 1.81 mol

c = 2 mol/L

V = n ÷ c = 1.81 mol ÷ 2 mol/L = 0.905 L = 905 mL

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TiliK225 [7]

Answer: The correct statements are ; A and B.

Explanation:

The strength of the magnetic field(B) in an electromagnet can be calculated using formula:

$B=\mu\frac{N}{L}I$

$\mu$ = Relative permeability

N = number of turns

I = Current in the wire of the solenoid

L = length of the solenoid or electromagnetic

As we can see from the formula:

$B\propto N$

$B\propto I$

So, by increasing the turns and increasing current flowing through wire one can increase the strength of an electromagnet.

Hence, the correct statements are ; A and B.

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3 years ago

Why are chemists interested in studying thermochemistry? a. Heat is often absorbed during reactions.b. Heat is often released du

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Answer:

a. Heat is often absorbed during reactions.

c. Heat is often released during chemical reactions.

Explanation:

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3 years ago

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2 years ago

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$sp^{3}$ , four electron domains, as in ethane $\text{C}_2\text{H}_6$
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$sp$ , two electron domains, as in ethyne $\text{C}_2\text{H}_2$

Molecules of each of the three hybridization demonstrate spatial configurations that would maximizes the separation between the electron domains.

Carbon atoms with a $sp^{3}$ hybridization would demonstrate a tetrahedral configuration with a bond angle of approximately $109.5\textdegree{}$
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Bond angles are characteristic of the spatial configuration of electron domains and identifies the hybridization of the central carbon atom.

Note that each hydrogen atom contains only one valence electron and would form only single bonds. It takes two valence electrons for oxygen atoms to achieve an octet such that each oxygen form only two bonds at a single time. Therefore given the fact that the carbon is bonded to both hydrogen and oxygen, only the following hybridizations are possible

$sp^{3}$ in which the oxygen atom forms a carbon-oxygen double bond with the central carbon atom;
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3 years ago

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2 years ago

Please I need help on these 3 questions. Thank You.​

Please I need help on these 3 questions. Thank You.