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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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Shkiper50 [21]
It is A I took it befor hope this helps:)
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2 years ago
Which type of stoichiometry problems does not require the use of molar mass?
Arlecino [84]

Answer:

Explanation:

It is volume-volume problems that does not require the use of molar mass.

7 0
2 years ago
Sulfuryl dichloride is formed when sulfur dioxide reacts with chlorine.
zubka84 [21]

<u>Answer:</u> The value of \Delta G^o of the reaction is 28.38 kJ/mol

<u>Explanation:</u>

For the given chemical reaction:

SO_2(g)+Cl_2(g)\rightarrow SO_2Cl_2(g)

  • The equation used to calculate enthalpy change is of a reaction is:

\Delta H^o_{rxn}=\sum [n\times \Delta H^o_f_{(product)}]-\sum [n\times \Delta H^o_f_{(reactant)}]

The equation for the enthalpy change of the above reaction is:

\Delta H^o_{rxn}=[(1\times \Delta H^o_f_{(SO_2Cl_2(g))})]-[(1\times \Delta H^o_f_{(SO_2(g))})+(1\times \Delta H^o_f_{(Cl_2(g))})]

We are given:

\Delta H^o_f_{(SO_2Cl_2(g))}=-364kJ/mol\\\Delta H^o_f_{(SO_2(g))}=-296.8kJ/mol\\\Delta H^o_f_{(Cl_2(g))}=0kJ/mol

Putting values in above equation, we get:

\Delta H^o_{rxn}=[(1\times (-364))]-[(1\times (-296.8))+(1\times 0)]=-67.2kJ/mol=-67200J/mol

  • The equation used to calculate entropy change is of a reaction is:

\Delta S^o_{rxn}=\sum [n\times \Delta S^o_f_{(product)}]-\sum [n\times \Delta S^o_f_{(reactant)}]

The equation for the entropy change of the above reaction is:

\Delta S^o_{rxn}=[(1\times \Delta S^o_{(SO_2Cl_2(g))})]-[(1\times \Delta S^o_{(SO_2(g))})+(1\times \Delta S^o_{(Cl_2(g))})]

We are given:

\Delta S^o_{(SO_2Cl_2(g))}=311.9J/Kmol\\\Delta S^o_{(SO_2(g))}=248.2J/Kmol\\\Delta S^o_{(Cl_2(g))}=223.0J/Kmol

Putting values in above equation, we get:

\Delta S^o_{rxn}=[(1\times 311.9)]-[(1\times 248.2)+(1\times 223.0)]=-159.3J/Kmol

To calculate the standard Gibbs's free energy of the reaction, we use the equation:

\Delta G^o_{rxn}=\Delta H^o_{rxn}-T\Delta S^o_{rxn}

where,

\Delta H^o_{rxn} = standard enthalpy change of the reaction =-67200 J/mol

\Delta S^o_{rxn} = standard entropy change of the reaction =-159.3 J/Kmol

Temperature of the reaction = 600 K

Putting values in above equation, we get:

\Delta G^o_{rxn}=-67200-(600\times (-159.3))\\\\\Delta G^o_{rxn}=28380J/mol=28.38kJ/mol

Hence, the value of \Delta G^o of the reaction is 28.38 kJ/mol

7 0
3 years ago
A- is a weak base. which equilibrium corresponds to the equilibrium constant ka for ha?
vekshin1

Answer:

K_a=\frac{[H^+][A^-]}{[HA]}

Explanation:

ka is defined as the dissociation constant of an acid. It is defined as the ratio of concentration of products to the concentration of reactants.

For the dissociation of weak acid, the chemical equation follows:

HA\rightleftharpoons H^++A^-

The equilibrium constant is defined by the equilibrium concentration of products over reactants:

K_a=\frac{[H^+][A^-]}{[HA]}

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3 years ago
What volume of a 0.200 M HCI solution is needed to neutralize 25.0 L of a 0.250 M NaOH solution? Follow these steps
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Answer: A little bit confused can you explain what I have to do

Explanation:

3 0
2 years ago
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