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Questions in chemistry

[Done] What causes the concentration of reactants to affect the reaction rate? A. It changes the molecular shape, removing orientation requirements. B. It breaks bonds that would have needed special orientation. C. It makes molecules less sensitive to proper orientation. D. It increases the number of collisions at the right orientation.

[Done] HCl (aq) and NaOH (aq)

[Done] 1. The simplest form of matter that cannot be broken down into a simpler substance 2. The part of a solution that dissolves the solute 3. The scattering and reflecting of light caused by the colloid particles 4. Formed when hydrogen is combined with oxygen through a chemical reaction 5. What the appearance of the components of a solution look like 6. Has to be added to the mixture to make a diluted solution 7. A type of mixture with components that are evenly distributed 8. A type of air pollution produced by combining smoke and fog

[Done] An electric device delivers a current of [tex]$15.0 A$[/tex] for 30 seconds. How many electrons flow through it?

[Done] a) A back titration is implemented in indigestion and constipation remedy analysis using a milk sample. A magnesia milk sample weighing 3.964 g and containing magnesium hydroxide, Mg(OH)2, was added to 60.00 mL of 0.350 M hydrochloric acid (HCl) in a conical flask. After the reaction was completed, the excess HCl in the conical flask required 30.45 mL of 0.216 M sodium hydroxide (NaOH) for titration to achieve the end point. Calculate the percentage (w/w) of the active ingredient Mg(OH)2 in the sample. The reaction: Mg(OH)2 + 2HCl → MgCl2 + CO2 + H2O b) Distinguish between end point and equivalence point.

[Done] When two ionic solutions (salts) are combined, the resulting mixture contains positive and negative ions from each solution. The mixing permits new combinations of ions. If one or more of these new ion combinations happen to be insoluble in water, it "falls out" of the solution as a solid compound. The insoluble product formed in this way is called a A. Discharge B. Precipitate C. Accelerant D. Deliberant

[Done] A sample of gas contains $6.25 \times 10^{-3} mol$ in a 500.0 mL flask at $265^{\circ} C$. What is the pressure of the gas in kilopascals? Formula: $P V=n R T(R=8.31 L \cdot kPa / mol \cdot K )$ Which variables are given? pressure volume temperature moles

[Done] What energy is required for a reaction to occur? A. Bond energy B. Potential energy C. Activation energy D. Kinetic energy

[Done] 13. The main reason for performing a back titration instead of a direct titration is: A. The reaction is too slow or weak for direct measurement B. It increases the error in the experiment C. It does not require a burette D. The titration curve is always linear

[Done] Look at the materials listed in the word bank. Tell whether the materials are elements or compounds. Write the materials under the proper columns. Word Bank: Silver Copper Hair spray Mist Water Iron Rust Whipped cream Rubbing alcohol Antiseptic solution | Pure Substances | Mixtures | |---|---| | Element | Compound | Homogeneous | Heterogeneous | | | | | |