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Questions in chemistry

[Answered] The chart shows the amount of solute that fully dissolved when added to 500 ml of water. | Solutions | Amount of Solute | | --------- | ---------------- | | X | 10 g | | Y | 12 g | | Z | 8 g | Which ranks the solutions in order of greatest to least solubility? A. [tex]$X \rightarrow Y \rightarrow Z$[/tex] B. [tex]$Y \rightarrow X \rightarrow Z$[/tex] C. [tex]$Z \rightarrow X \rightarrow Y$[/tex] D. [tex]$Y \rightarrow Z \rightarrow X$[/tex]

[Answered] The table shows the percentages of hydrocarbons that are found in a sample of crude oil. | Hydrocarbons | Percentage | |---|---| | paraffins | 30 | | naphthenes | 49 | | aromatics | 15 | | asphaltics | 6.0 | Based on the given information, what is the best classification for this sample of crude oil? A. an element B. a pure compound C. a pure substance D. a mixture

[Answered] Which of the following equations is not balanced? [tex]2 Al +6 HCl \rightarrow 2 AlCl _3+3 H _2[/tex] [tex]2 Na +2 H _2 O \rightarrow 2 NaOH + H _2[/tex] [tex]SO _2+ O _2 \rightarrow SO _3[/tex] [tex]C _3 H _8+5 O _2 \rightarrow 3 CO _2+4 H _2 O[/tex] [tex]2 H _2+ O _2 \rightarrow 2 H _2 O[/tex]

[Answered] Is oxygen a metal or a nonmetal? How many valence electrons does an oxygen atom have? Will sulfur and oxygen atoms most likely form an ionic bond or a covalent bond?

[Answered] All atoms of an element have the same number of A. protons plus neutrons B. neutrons C. electrons D. protons

[Answered] Which fire extinguisher would be most effective when fighting a fire where wood, paper, and flammable liquids are burning? A. Carbon dioxide (CO2) B. Water C. Foam or ABC dry chemical D. All of the above will work on fires where wood, paper, and flammable liquids are burning

[Answered] Consider the nuclear equation below. ${ }_{66}^{222} Rn \longrightarrow{ }_{84}^{210} Po+{ }_2^4 He$ Which is the missing value that will balance the equation? A. 84 B. 86 C. 88 D. 90

[Answered] Which property of a substance can be determined using a pH indicator? A. acidity B. boiling point C. density D. electrical conductivity E. thermal conductivity

[Answered] What is the natural state of mercury, Hg? A. solid B. gas C. liquid

[Answered] Select all the correct answers. Which equations represent precipitation reactions? [tex]$Na _2 S+ FeBr _2 \rightarrow 2 NaBr + FeS$[/tex] [tex]$MgSO _4+ CaCl _2 \rightarrow MgCl _2+ CaSO _4$[/tex] [tex]$LiOH + NH _4 I \rightarrow Lil + NH _4 OH$[/tex] [tex]$2 NaCl + K _2 S \rightarrow Na _2 S+2 KCl$[/tex] [tex]$AgNO _3+ NaCl \rightarrow AgCl + NaNO _3$[/tex]