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Alexxx [7]
3 years ago
11

During science lab, some students added small pieces of magnesium ribbon to 10 mL of hydrochloric acid. They noticed that bubble

s formed, the test tube got hot, and the magnesium disappeared.
Which is a sign that a chemical reaction has taken place in this experiment?
Chemistry
2 answers:
stiv31 [10]3 years ago
4 0
Your answer would be a change in odor! Hope this helps! ;D
Stels [109]3 years ago
4 0

Answer:

C

Explanation:

Release of heat energy

The test tube got hot; that's a sign that heat energy is being released. This is an exothermic chemical reaction. Change in odor and color are signs of a chemical change but do not occur in this case.

(Correct in USA Test Prep too!)

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Answer:

<u>Matter</u>

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4 0
3 years ago
A 700.0 mL gas sample at STP is compressed to a volume of 200.0 mL, and the temperature is increased to 30.0°C. What is the new
dolphi86 [110]

Answer: The new pressure of the gas in Pa is 388462

Explanation:

Combined gas law is the combination of Boyle's law, Charles's law and Gay-Lussac's law.

The combined gas equation is,

\frac{P_1V_1}{T_1}=\frac{P_2V_2}{T_2}

where,

P_1 = initial pressure of gas at STP = 10^5Pa

P_2 = final pressure of gas = ?

V_1 = initial volume of gas = 700.0 ml

V_2 = final volume of gas = 200.0 ml

T_1 = initial temperature of gas = 273 K

T_2 = final temperature of gas = 30^oC=273+30=303K

Now put all the given values in the above equation, we get:

\frac{10^5\times 700.0ml}{273K}=\frac{P_2\times 200.0ml}{303K}

P_2=388462Pa

The new pressure of the gas in Pa is 388462

6 0
3 years ago
Consider the chemical equation. CuCl2 + 2NaNO3 mc023-1.jpg Cu(NO3)2 + 2NaCl What is the percent yield of NaCl if 31.0 g of CuCl2
lana [24]
CuCl2 + 2NaNO3 ---->  Cu(NO3)2 + 2NaCl

using molar masses:-
Theoretical yields:-
63.54 + 2(35.45) g  of CuCl2  produces  2(22.98 + 35.45) g of NaCl
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5 0
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Answer:

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Explanation:

hope hope this helps!

6 0
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