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Gekata [30.6K]
3 years ago
7

Sarah heated some orange coloured crystals in a test tube. The crystals turned green and fizzed. After the fizzing stopped, the

test tube was allowed to cool. A green powder was left in the tube. Determine whether a chemical or a physical reaction has occurred. Identify two observations that support your decision.
Chemistry
1 answer:
Anni [7]3 years ago
6 0
A chemical change has occurred.
This is indicated by a colour change occurring (from orange to green) as well as a gas being given off (seen as the fizzing). If the fizzing made a small amount of noise, it also indicates that sound energy is given off, which is another indication that a chemical reaction has occurred.
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A gas at 20.0°C and 52.1 mL is heated to 93.5°C. What is the new volume?
lawyer [7]
\frac{ V_{1} }{ T_{1} } = \frac{ V_{2} }{ T_{2} }
V_{1} = 0.0521 L
T_{1} = 293.15 K
T_{2} = 366.65 K

Solve for V_{2}

\frac{0.0521 L}{293.15 K} = \frac { V_{2} }{366.65 K}

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Atomic weight of 20 elements
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3 years ago
When HClO2 is dissolved in water, it partially dissociates according to the equation
Natasha_Volkova [10]

Answer:

x = 100 * 1.1897 = 118.97 %, which is > 100 meaning that all of the HClO2 dissociates

Explanation:

Recall that , depression present in freezing point is calculated with the formulae = solute particles Molarity x KF

0.3473 = m * 1.86

Solving, m = 0.187 m

Moles of HClO2 = mass / molar mass = 5.85 / 68.5 = 0.0854 mol

Molality = moles / mass of water in kg = 0.0854 / 1 = 0.0854 m

Initial molality

Assuming that a % x of the solute dissociates, we have the ICE table:

                 HClO2         H+    +   ClO2-

initial concentration:       0.0854                    0             0

final concentration:      0.0854(1-x/100)   0.0854x/100   0.0854x / 100

We see that sum of molality of equilibrium mixture = freezing point molality

0.0854( 1 - x/100 + x/100 + x/100) = 0.187

2.1897 = 1 + x / 100

x = 100 * 1.1897 = 118.97 %, which is > 100 meaning that all of the HClO2 dissociates

3 0
4 years ago
Question 4
Anni [7]

Answer:

as

Explanation:

as

8 0
3 years ago
0.00035 scientific notation<br><br>​
inessss [21]
3.5 x 10^-4 is the answer ! :)
6 0
3 years ago
Read 2 more answers
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