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Questions in chemistry

[Done] If the activation energy required for a chemical reaction were reduced, what would happen to the rate of the reaction? A. The rate would increase. B. The rate would decrease. C. The rate would remain the same. D. The rate would be zero.

[Done] In a group assignment, students are required to fill 10 beakers with [tex]$0.720 M CaCl _2$[/tex]. If the molar mass of [tex]$CaCl _2$[/tex] is 110.98 g/mol and each beaker must have [tex]$250 . mt$[/tex] of solution, what mass of [tex]$CaCl _2$[/tex] would be used? Use molarity [tex]$=\frac{\text { moles of solute }}{\text { Iters of solution }}$[/tex].

[Done] Select all the correct answers. A sample of an unknown compound has a percent composition of $52.14 \%$ carbon, $13.13 \%$ hydrogen, and $34.73 \%$ oxygen. Which compounds could the sample be? $CH _3 CH _3 CH _2 O _2$ $C _2 H _5 OH$ $C _4 H _{10} O _2$ $C _4 H _{12} O _2$

[Done] Consider the chemical equation in equilibrium: [tex]$A(g)+2 B(g) \Leftrightarrow C(g)+D(g)+\text { heat }$[/tex] What will happen to the equilibrium of this reaction if the temperature is increased? A. It will shift to the left because heat is released. B. It will shift to the left because heat is absorbed. C. It will shift to the right because heat is released.

[Done] Which type of chemical reaction occurs in $C _6 H _{12}+9 O _2 \rightarrow 6 CO _2+6 H _2 O$? A. synthesis B. combustion C. single replacement D. double replacement

[Done] Commonly called laughing gas, what are the molecular and empirical formulas of this substance? A. C2O2, CO2 B. C4O, CO C. CO2, CO₂ D. C402, C20 E. C₂O, CO2

[Done] Codeine to morphine? A. Oxidation B. Dealkylation C. Reduction D. Hydrolysis

[Done] What is [tex]$K_{ a }$[/tex] for [tex]$H _2 CO _3(a q)= H ^{+}(a q)+ HCO _3{ }^{-}(a q)$[/tex]? A. [tex]$K_2=\frac{\left[ H _2 CO _3\right]}{\left[ H ^{+}\right]\left[ HCO _3{ }^{-}\right]}$[/tex] B. [tex]$\left.K_a=\left[ H _2 CO _3\right] H + NH HCO _3\right]$[/tex] C. [tex]$K_{ a }=\left[ H ^{+}\right]\left[ HCO _3{ }^{-}\right]$[/tex] D. [tex]$K_3=\frac{| H +| HCO -|}{\left| H _2 CO _3\right|}$[/tex]

[Done] Give 5 samples of mixtures and classify each as homogeneous or heterogeneous. Explain the findings. HOMOGENEOUS AND HETEROGENEOUS MIXTURES A homogeneous mixture has a uniform composition. In contrast, the composition of a heterogeneous mixture varies depending on where you sample it. Identify each mixture as either homogeneous or heterogeneous. Examples: 1. Air 2. Potting soil 3. Gasoline 4. Cereal and milk 5. Sugar water 6. Coffee 7. Tossed salad 8. Vinegar 9. Soda with ice 10. Natural gas

[Done] Which is a typical characteristic of an ionic compound? A. The ionic compound has a high melting point. B. The ionic compound is described as a molecule. C. The ionic compound has a low solubility in water. D. Electron pairs are shared among atoms.