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Pavel [41]
2 years ago
5

Question 21 of 25 Which of the following requires a chemical change?

Chemistry
2 answers:
Vesna [10]2 years ago
3 0

Answer:

c . Letting the fizz escape from a soda

lilavasa [31]2 years ago
3 0
Answer: a

because there is a fire, it is a chemical change causing the marshmallow to melt.
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Can someone please help me with this question??
dsp73
I think the answer is b
5 0
3 years ago
How would you prepare 175 mL of a 0.350kmol/m^3 calcium nitrate solution
SVEN [57.7K]
0,35 kmol/m³ = 0,35 mol/dm³ = 0,35 mol/L
175 mL = 0,175 L
*-*-*-*-*-*-*-*-*-*-*-*
C = n/V
n = 0,35×0,175
n = 0,06125 mol

mCa(NO₃)₂: 40+(14×2)+(16×6) = 164 g/mol

1 mol --------- 164g
0,06125 ---- X
X = 10,045g

To prepare 175 mL of 0,35M solution, add 10,045g of calcium nitrate and add water to a volume of 175ml.
3 0
3 years ago
The highest energy level of sodium contains ________ electron(s).
Effectus [21]

Answer:

A

Explanation:

The group number of an element is equal to the number of electrons the outermost shell (or highest energy level) contains

8 0
4 years ago
The rate law for the reaction 3a ⟶⟶ c is rate = 4. 36 x 10–2 l • mol–1 • h–1[ a ]2 how long will it take in hours for the concen
Paha777 [63]

The hours taken for concentration to decrease from 0 to 74 min. to 0.21 m is 91.7 hours.

<h3>What is the rate law of a reaction?</h3>

Rate law depicts the rate of a chemical reaction depend on the concentration of the reactant.

The given reaction is second order reaction

Thus, the hours taken for concentration to decrease from 0 to 74 min. to 0.21 m is 91.7 hours.

Learn more about rate law of a reaction

brainly.com/question/8314253

#SPJ4

4 0
2 years ago
A. What is the pH of a solution with a [H+] of 6.8 x 10^-11?
inysia [295]

Answer:

[H+] = 6.8×10^-11

so, pH = - log[H+]

= - log [6.8×10^-11]

= -(-10.167)

= 10.167

6 0
2 years ago
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