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Questions in chemistry

📝 Answered - Andy has two samples of liquids. Sample A has a pH of 4, and sample B has a pH of 6. What can Andy conclude about these two samples?

📝 Answered - A solution has a pH of 2. Which best describes the solution? A. a strong acid B. a strong base C. a neutral solution D. a weak base

📝 Answered - Which of the following causes a chemical change? A. metabolizing fat B. winding an alarm clock C. slicing a tomato D. pumping gasoline E. digging a hole

📝 Answered - For the equation [tex]BaCl _2+ Na _2 SO _4 \rightarrow BaSO _4+2 NaCl[/tex], how many chlorine atoms are on the reactants side and on the products side? A. reactants: 1 ; products: 1 B. reactants: 1 ; products: 2 C. reactants: 2 ; products: 1 D. reactants: 2 ; products: 2

📝 Answered - Which chemical or physical change is an exothermic process? A. the baking of cookies B. the combustion of gasoline C. the evaporation of water from a pool D. the cold pack reaction $\left( NH _4 NO _3+ H _2 O +\right.$ heat $\rightarrow NH _4 OH + HNO _3$ )

📝 Answered - 2 3 5 7 Which element has the greatest average atomic mass? A. iodine B. bromine C. tellurium D. krypton

📝 Answered - In the reaction $MgCl _2+2 KOH \rightarrow Mg ( OH )_2+2 KCl$, if 3 moles $MgCl _2$ are added to 4 moles KOH, what determines how much $Mg ( OH )_2$ is made? A. The amount of KOH B. The amount of KCl C. The amount of $MgCl _2+ KOH$ D. The amount of $MgCl _2$

📝 Answered - Determine the number of valence electrons in an argon atom.

📝 Answered - Type the correct answer in the box. Round your answer to the nearest hundredth. Element $X$ has two isotopes. The table gives information about these isotopes. | Isotope | Atomic Mass (amu) | Abundance (%) | |---|---|---| | $X-63$ | 62.9296 | 69.15 | | $X-65$ | 64.9278 | 30.85 | The average atomic mass of element $X$ is $\square$ amu.

📝 Answered - Given the following table: | color | dull gray | | ------------------- | ------------------------------ | | density | $11.3 g / cm ^3$ | | volume of sample | $3.00 cm^3$ | | melting point | $327^{\circ} C$ | | reaction with air | lead oxide forms on the surface | | electrical conductivity | conducts some electricity | Which statement is true with respect to the investigation? A. The student investigated only the physical properties of lead. B. The student investigated only the chemical properties of lead. C. The student investigated more physical properties than chemical properties of lead. D. The student investigated more chemical properties than physical properties of lead.