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2 years ago

Assertion (A): Naphthalene balls disappear with time without leaving any solid.

Chemistry

2 answers:

gogolik [260]2 years ago

7 0

Explanation:

a) Both A and R are true and R is the correct

explanation of A.

Kruka [31]2 years ago

7 0

Answer:

$\fbox {c) A is true but R is false.}$

Explanation:

Assertion (A):

⇒ Naphthalene balls disappear with time without leaving any solid.

⇒ True √

Reason (R):

⇒ Solid converted to liquid is called sublimation.

⇒ False ×

⇒ Solid converted to liquid is called melting

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To determine the concentration of a sample of calcium hydroxide, 1.45M HCl is added drop-wise using a burst. Write the balanced

GenaCL600 [577]

Answer:

H^+(aq) + OH^-(aq) —> H2O(l)

Explanation:

We'll begin by writing the balanced equation for the reaction.

2HCl(aq) + Ca(OH)2(aq) —> CaCl2(aq) + 2H2O(l)

Ca(OH)2 is a strong base and will dissociates as follow:

Ca(OH)2(aq) —> Ca^2+(aq) + 2OH^-(aq)

HCl is a strong acid and will dissociates as follow:

HCl(aq) —> H^+(aq) + Cl^-(aq)

Thus, In solution a double displacement reaction occurs as shown below:

2H^+(aq) + 2Cl^-(aq) + Ca^2+(aq) + 2OH^-(aq) —> Ca^2+(aq) + 2Cl^-(aq) + 2H2O(l)

To get the net ionic equation, cancel out Ca^2+ and 2Cl^-

2H^+(aq) + 2OH^-(aq) —> 2H2O(l)

H^+(aq) + OH^-(aq) —> H2O(l)

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3 years ago

Arsenic reacts with chlorine to form a chloride if 1.587 g of arsenic reacts with 3.755 g of chlorine what is the simplest formu

Marina CMI [18]

Determining the number chloride molecules that will result from this reaction requires we first determine the number of moles of arsenic and the number of moles of chlorine on hand.

1.587 grams of arsenic divided by its atomic weight of 74.92 grams per mole results in 0.0212 moles.

We do the same for chlorine. 2.755 grams of chlorine divided by 35.45 grams per mole gives us 0.106 moles.
0.106 moles divided by .0212 moles equals 5; therefore, the simplest formula of the chloride produced will be AsCl₅.

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3 years ago

A second-order reaction has a rate constant of 1.25 M-1 s-1. If the initial reactant concentration is 1.0 M (a) determine the ha

Ne4ueva [31]

Answer:

(a) 0.8 s

(b) t = 7.2 s

Explanation:

(a) Half life expression for second order kinetic is:

$t_{1/2}=\frac{1}{k[A_o]}$

Where,

$[A_o]$ is the initial concentration = 1.0 M

k is the rate constant = 1.25 M⁻¹s⁻¹

So,

$t_{1/2}=\frac{1}{1.25\times 1.0}$

Half life = 0.8 s

(b) Integrated rate law for second order kinetic is:

$\frac{1}{[A_t]} = \frac{1}{[A]_0}+kt$

Where, $[A_t]$ is the final initial concentration

For 90% completion, 10% is left. so,

$[A_t]=\frac {10}{100}\times 1.0=0.1\ M$

So,

$\frac{1}{0.1} = \frac{1}{1.0}+1.25t$

t = 7.2 s

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3 years ago

State why vulcanologist make predications about when a volcano will erupt

olasank [31]

Answer:

They want to know how long it has been since it last erupted.

Explanation:

Scientists study a volcano's history to try to predict when it will next erupt. They also want to know the time span between its previous eruptions

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3 years ago

What is a homogenous mixtures

Veronika [31]

Answer:

Explanation:

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3 years ago

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