Chromate ions react according to the following equation, where the left side of the reaction is yellow and the right side is orange.
CrO42– + 2H+ ⇄ Cr2O72– + H2O
A student adds sodium hydroxide (NaOH) to the solution at equilibrium. In one to two sentences, describe and explain any changes to the solution that the student will observe.
SOMEONE HELP!!!
1. Which phrase defines chemical equilibrium?
a state in which the forward and reverse reactions are proceeding at equal rates
2. Use the table of data for a decomposition reaction to answer the question.
Concentration (C) at T1 (g/L)C at T2 (g/L)C at T3 (g/L)C at T4 (g/L)Reactant3001005050Product 10100125125Product 20100125125
In a decomposition reaction, a reactant breaks down to form two products. At which time did the system first reach chemical equilibrium?
T3
3. Use the dissociation reaction to answer the question.
FeSCN2+(aq) ⇄ Fe3+(aq) + SCN-(aq)
In the reaction, FeSCN2+ ions are red, Fe3+ ions are pale yellow, and SCN- ions are colorless.
A solution at equilibrium is yellow-orange. The concentration of SCN- ions is increased by a moderate amount. Which color will the solution most likely become?
orange
4. Use the reaction to answer the question.
N2O4(g) + energy ⇄ 2NO2(g)
The system is at equilibrium, but then it is subjected to an increase in pressure. Which change will happen?
The rate of the reverse reaction will increase, which will decrease the number of particles in the system.
5. According to Le Chatelier's principle, what happens when changes are made to a system that includes reversible chemical reactions in equilibrium?
Opposing changes will work to bring the system back to equilibrium.
6. A system is at equilibrium. Which statement correctly describes the effect on the forward and reverse reaction rates if reactants are added to the system?
The forward reaction rate becomes faster than the reverse reaction rate.
7. Which effect is a likely direct negative result of deforestation?
landslides
8. Which goal do all environmental regulations for industry serve?
to protect people and the environment
9. Why is it difficult to make vaccines for viruses?
All known vaccine molecules must be tested to find the right one.
10. Who can be particularly negatively affected by ion exchange water purification systems?
people with high blood pressure who need to avoid sodium
11. A city is considering different water purification methods for the water supply. Which fact would help inform the city if cost was a significant constraint?
Reverse osmosis systems are more expensive because of the use of filters that need replacement.
12. Criteria and constraints help determine which solutions will be applied when extracting materials from pomace. In which way might a specific criterion be applied to this situation?
The use of pomace for animal feed might be chosen if minimizing production costs is desired.
13. Which substance would one hope to extract from pomace?
fruit flavorings
14. Which microscopic properties allow Kevlar and spider silk to be so strong?
strong chains of molecules and intermolecular forces between layers
15. Which property of spider silk is NOT shared by Kevlar?
biodegradability
16. There are several ways to optimize metal extraction. Which way also optimizes environmental impact?
sifting ore at the site before transporting
17. An engineer is tasked with building a new structure in Seattle that can withstand frequent rainy weather. Which alloy is the best choice for building this structure?
iron plus nickel for corrosion resistance
18. Use the equation of sodium chloride dissolving in water to complete the activity.
NaCl(s) ⇄ Na+(aq) + Cl-(aq)
A student is testing two clear liquids. One liquid is water that has been modified to have a basic pH. The other liquid is a sports drink that contains added electrolytes, including Na+(aq). How can the student use the equilibrium reaction of sodium chloride to determine which liquid is which? In three to five sentences, explain your answer.
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19. Chromate ions react according to the following equation, where the left side of the reaction is yellow and the right side is orange.
CrO42- + 2H+ ⇄ Cr2O72- + H2O
A student adds sodium hydroxide (NaOH) to the solution at equilibrium. In one to two sentences, describe and explain any changes to the solution that the student will observe.
...
20. In one to two sentences, explain why metal is often used for making wire and the properties that make metal useful.
Surpassed only by silver, copper is a highly conductive metal. This means electricity can pass through it with greater ease, making it ideal for use in electrical wires. Companies can use other conductive metals to create electrical wires.