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Nadusha1986 [10]
3 years ago
10

Which is the most important question for deciding if a chemical reaction has occurred

Chemistry
2 answers:
cluponka [151]3 years ago
6 0
A chemical reaction undergoes a chemical change so the question you should ask if a chemical reaction has occurred is "Did a chemical change happened?". Chemical change in a reaction happens when you see bubbles, when the reaction increases or decreases in temperature or a precipitate is formed.
anastassius [24]3 years ago
4 0

Answer:

the answer is Was there any heat energy given off?

Explanation:

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The following is a procedure that was theoretically performed by a student. Read through the procedure and answer the questions
yKpoI14uk [10]

Answer:

CaCl2 (aq) + K2CO3(aq) ---------> CaCO3(s) + 2KCl(aq)

Explanation:

We have the reactants as calcium chloride and potassium carbonate. Recall that we are expecting that the reaction will yield a precipitate. We must keep that in mind as we seek to write its balanced chemical reaction equation.

So we now have;

CaCl2 (aq) + K2CO3(aq) ---------> CaCO3(s) + 2KCl(aq)

Recall that the rule of balancing chemical reaction equation states that the number of atoms of each element on the right side of the reaction equation must be the same as the number of atoms of the same element on the left hand side of the reaction equation.

6 0
3 years ago
1. Use your knowledge of valence electrons and how they affect bonds to figure out how carbon (Group 14) and oxygen (Group 16) w
erik [133]

From the fact that oxygen is in group 16 and carbon is in group 14, the structure of CO2 must be O=C=O. In methane, there is no bond between any of the hydrogen atoms. The structure of H2O2 is H–O–O–H.

Carbon is in group 14 hence it has four valence electrons and oxygen is in group 16 hence it has six valence electrons. This implies that each oxygen atom will share four electrons with carbon in a covalent bond to form the structure O=C=O.

In CH4, we know that carbon is tetravalent so it forms for bonds. Therefore, there is no bond between hydrogen atoms so it bonds with each hydrogen atom; hydrogen only forms one bond.

In H2O2, there is the peroxide ion that has the structure O-O. Hence, the correct structure of H2O2 is H–O–O–H.

Learn more: brainly.com/question/24775418

5 0
3 years ago
A container holds 15.0 g of phosphorous gas at a pressure of 2.0 atm and a temperature of 20.0 Celsius. What is the density of t
erik [133]
<span>Density is a value for mass, such as kg, divided by a value for volume, such as m3. Density is a physical property of a substance that represents the mass of that substance per unit volume. We calculate as follows:

PV = nRT
PV = mRT/ Molar mass
m/V = P(molar mass)/RT
Density = P(molar mass)/RT 
Density = 2.0 ( 30.97 ) / 0.08206 ( 20 + 273.15) = 2.57 g/L <----First option</span>
5 0
3 years ago
Read 2 more answers
What is the purpose of adding phenolphthalein to your Erlenmeyer flask prior to starting a titration?
koban [17]

Answer:

a. The phenolphthalein acts as a color changing indicator to signal the endpoint of the reaction.

Explanation:

Phenolphthalein is an organic substance with chemical formula C_{20}H_{14}O_{4}.

It is a substance commonly used in acid-base titrations to indicate the end point in the titration because phenolphthalein is colorless in acidic solutions but turns a purplish-pink color in basic solutions.

In this way it helps visually to notice when the final point of the titration has been reached.

3 0
3 years ago
Help please need to find the frequency of the wave
Lapatulllka [165]
E=hf h=6.63*10^-34 f=8.66*10^14 E=6.63*10^-34*8.66*10^14=57.4*10^-20 joules
3 0
3 years ago
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