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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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What is the mass of disulfur pentoxide (S2O5)?
Fittoniya [83]

Answer: What is the mass of disulfur pentoxide (S2O5)?

Explanation:144.14g/mol

5 0
3 years ago
What is the pH of a solution after the addition of 30.0 mL of 0.100 M NaOH to 50.0 mL of 0.10 M HBr?
Pani-rosa [81]

Answer:

pH = 1.6

Explanation:

  • HBr + NaOH ⇒ NaBr + H2O

0 mL NaOH:

  • HBr ↔ H3O+  +  Br-

⇒ [ H3O+] = M HBr = 0.1 M

⇒pH = -log [H3O+] = 1

30 mL NaOH:

⇒ mol NaOH = 0.1 mol / L * 0.03 L =  3 E-3 mol

⇒ mol HBr = 0.05 L * 0.1 mol/L = 5 E-3 mol

⇒ M HBr = ( 5 E-3 mol - 3 E-3 mol) / 0.08 L = 0.025 M

⇒ pH = - log (0.025) = 1.6

7 0
3 years ago
The 85.2-g sample of the compound x4o10 contains 48.0 g of oxygen atoms. what is the molar mass of element x?
Vedmedyk [2.9K]
X4O10
Let molar mass of X be y
molar mass =  4y + 10 x 16 = 4y+160

so, moles = 85.2 / (4y+160)

Moles of oxygen = 10 x [85.2 / (4y+160) ]
Mass of oxygen  = 16 x 10 x [85.2 / (4y+160) ]
which is 48.0

so, 48 = 16 x 10 x [85.2 / (4y+160) ]

Solve the equation to get y.

y = 31
5 0
2 years ago
Question 10
olga2289 [7]

Answer:

Here it would be A,B and C because all the examples are violating safety precautions. They are all examples of un safe signs.

Hope this helps

Explanation:

6 0
2 years ago
What about this one y'alllll
densk [106]

Answer:

um.. is this a quiz or what girl...

6 0
3 years ago
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