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3 years ago

Which of the following statements holds true for chemical change?

1 answer:

4 0

Which of the following statements holds true for chemical charge?

Correct Answer: C) In a chemical charge, the molecular structure of substance charges

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A student noticed that the size of the hot pack becomes bigger when magnesium sulfate reacts with water. She thinks that more at

cestrela7 [59]

Answer:

Disagree with the suggestion based on the hygroscopic nature of anhydrous magnesium sulfate

Explanation:

Magnesium sulfate in the anhydrous form is a drying agent. A drying agent salts of inorganic compounds that has the capability of absorbing water to become hydrated, when placed in the presence of a wet surface or moist air

Anhydrous magnesium sulfate is therefore hygroscopic such that it absorbs water from the atmosphere and becomes hydrated and increases in size as its volume is increased according to the following chemical equation

MgSO₄(s) + 7H₂O(l) → MgSO₄·7H₂O(s)

The molar mass of anhydrous magnesium sulfate = 120.366 g/mol

The molar mass of the heptahydrate = 246.47 g/mol

Therefore, the mass of the magnesium sulfate doubles when it forms the heptahydrate, and the magnesium sulfate grows bigger.

4 0

3 years ago

When determining the density of a pure liquid or solution the temperature of the sample must be measured what is the density of

Whitepunk [10]

Idk I just need points sorry man

3 0

3 years ago

Picric acid has been used in the leather industry and in etching copper. However, its laboratory use has been restricted because

olchik [2.2K]

Answer:

0.3023 M

Explanation:

Let Picric acid = $H_{picric}$

So, $H_{picric}$ + $H_2}O$ ⇄ $H_3}O^+$ + $Picric^-$

The ICE table can be given as:

$H_{picric}$ + $H_2}O$ ⇄ $H_3}O^+$ + $Picric^-$

Initial: 0.52 0 0

Change: - x + x + x

Equilibrium: 0.52 - x + x + x

Given that;

acid dissociation constant ( $K_a$ ) = 0.42

$K_a = \frac{[H_3O^+][Picric^-]}{H_{picric}}$

$0.42 = \frac{[x][x]}{0.52-x}}$

$0.42 = \frac{[x]^2}{0.52-x}}$

0.42(0.52-x) = x²

0.2184 - 0.42x = x²

x² + 0.42x - 0.2184 = 0 -------------------- (quadratic equation)

Using the quadratic formula;

$\frac{-b+/-\sqrt{b^2-4ac} }{2a}$ ; ( where +/- represent ± )

= $\frac{-0.42+/-\sqrt{(0.42)^2-4(1)(-0.2184)} }{2*1}$

= $\frac{-0.42+/-\sqrt {0.1764+0.8736} }{2}$

= $\frac{-0.42+\sqrt {1.0496} }{2}$ OR $\frac{-0.42-\sqrt {1.0496} }{2}$

= $\frac{-0.42+1.0245}{2}$ OR $\frac{-0.42-1.0245}{2}$

= $\frac{0.6045}{2}$ OR $-\frac{1.4445}{2}$

= 0.30225 OR - 0.72225

So, we go by the +ve integer that says:

x = 0.30225

x = [ $H_3}O^+$ ] = [ $Picric^-$ ] = 0.3023 M

∴ the value of [H3O+] for an 0.52 M solution of picric acid = 0.3023 M (to 4 decimal places).

6 0

3 years ago

What is SiCl4 written out?

IgorLugansk [536]

Answer:

Silicon tetrachloride

Explanation:

7 0

3 years ago

HELP ASAP!!!!!!!!!!

weqwewe [10]

Answer:

D) food that a chef seal in a plastic bag and cook under a controlled temperature condition.

Explanation:

Sous vide, also known as low temperature long time cooking, is a method of cooking in which food is placed in a plastic pouch or a glass jar and cooked in a water bath for longer than usual cooking times at a precisely regulated temperature.

8 0

3 years ago