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Questions in chemistry

📝 Answered - A certain amount of NaOH is dissolved in 98.0 g of water at 25 °C. The final volume of NaOH solution is 100 mL. Given the density of the solution is 1.33 g/mL at 25 °C, calculate the number of moles of NaOH used.

📝 Answered - Batteries are hazardous because they A. contain flammable liquid B. contain asbestos C. contain acid D. emit a poisonous

📝 Answered - What is the name of the compound HF (aq)? Options: - Hydrofluoric acid - Fluorous acid - Fluoric acid - Hydrogen fluoride

📝 Answered - Ethylene oxide and methylene chloride are industrial processes. A. harmless materials B. carcinogens C. radioactive materials D. Both B and C are correct.

📝 Answered - Consider the following intermediate chemical equations. [tex] \begin{array}{ll} C(s)+O_2(g) \rightarrow CO_2(g) & \Delta H_1=-393.5 kJ \\ 2 CO(g)+O_2(g) \rightarrow 2 CO_2(g) & \Delta H_2=-566.0 kJ \\ 2 H_2 O(g) \rightarrow 2 H_2(g)+O_2(g) & \Delta H_3=483.6 kJ \end{array} [/tex] The overall chemical equation is [tex]$C ( s )+ H _2 O ( g ) \rightarrow CO ( g )+ H _2(g)$[/tex]. To calculate the final enthalpy of the overall chemical equation, which step must occur? A. Reverse the first equation, and change the sign of the enthalpy. Then, add. B. Reverse the second equation, and change the sign of the enthalpy. Then, add. C. Multiply the first equation by three, and triple the enthalpy. Then, add. D. Divide the third equation by two, and double the enthalpy. Then, add.

📝 Answered - Outline the essential steps and the chemistry involved in the qualitative and quantitative determination of nitrogen (Kjeldahl's method) in an organic compound. Describe briefly the principles and procedures involved in the determination of the presence of halogen in an organic compound which contains no nitrogen or sulphur. Write equations for the essential reactions involved in the procedures. Explain briefly the procedure and the chemistry involved in the quantitative determination of carbon and hydrogen in an organic compound.

📝 Answered - Describe the following states of matter (solid, liquid, and gas) according to their: 1. Properties 2. Arrangement of particles 3. Motion of particles

📝 Answered - Determine the polarity (polar or nonpolar) and the type of intermolecular forces of attraction (IMFA) for the following compounds: | Compound | Polarity (Polar or Nonpolar) | Type of IMFA | |---|---|---| | H₂O (water) | polar | H-bonding | | XeF₄ (xenon tetrafluoride) | | | | Acetone | | | | O₃ (ozone) | | | | SF₆ (sulfur hexafluoride) | | | | H-C≡N: (hydrogen cyanide) | | | Molecular structures: Water: H-O-H Acetone: H-C-C-C-H Ozone: O=O-O Xenon tetrafluoride: F-Xe-F | F | F Sulfur hexafluoride: F-S-F | F | F Hydrogen cyanide: H-C≡N

📝 Answered - The number of protons, on the other hand, has remained the same. How many protons are present in the nucleus of chlorine, whether it is in its elemental state or an ionic state?

📝 Answered - Which of the following reactions shows a physical change? A. [tex]$H _2(g)+ O _2(g) \rightarrow H _2 O ( l )$[/tex] B. [tex]$2 AgNO _3(a q)+ CaBr _2(a q) \rightarrow 2 AgBr (s)+ Ca \left( NO _3\right)_2(a q)$[/tex] C. [tex]$2 CH _3 OH ( l )+3 O _2(g) \rightarrow 2 CO _2(g)+4 H _2 O ( l )$[/tex] D. [tex]$NaCl (s) \rightarrow NaCl (a q)$[/tex]