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Questions in chemistry

[Answered] D. an opposite charge and the same mass 82. Which of the following atom consists of exactly fifteen protons? A. P-32 B. S-32 C. O-15 D. N-15 83. Which of the following three groups represent the most elements classified as metalloids in the periodic table? A. 1, 2 & 3 B. 2, 13 & 14 C. 14, 15 & 16 D. 16, 17 & 18 84. When a metallic atom combines with a non-metallic atom, the non-metallic atom will... A. lose electrons and its size will decrease B. lose electrons and its size will increase C. gain electrons and its size will decrease D. gain electrons and its size will increase 85. Which of the following is a binary compound? A. Hydrogen sulphide B. Hydrogen sulphite C. Ammonium sulphide D. Ammonium sulphate 86. Some students are asked to describe differences between gases and liquids. Three of their suggestions are: I) Gas molecules are further apart II) Gas molecules are smaller III) Liquid molecules vibrate around fixed positions Which suggestions are correct? A. II only B. II only C. III only D. All of the above

[Answered] An experimenter attempts to carry out a single replacement reaction between solid potassium and a solution of hydrogen iodide. Which is more reactive - potassium or hydrogen? Which of the following equations correctly predicts the products of the reaction? i. $2 K_{( s )}+2 HI _{( aq )} \rightarrow I _{2( l )}+2 HK _{( aq )}$ ii. $K _{( s)}+ HI _{( aq )} \rightarrow KHI _{( s )}$ iii. $2 K_{( s)}+2 HI _{( aq )} \rightarrow H _{2(g)}+2 KI _{( aq )}$ iv. $K _{( s)}+ HI _{( aq )} \rightarrow$ no reaction

[Answered] Fill in the systematic names of the following chemical compounds. Note: for compounds containing hydrogen, you may give the common name instead. | molecular formula | name of compound | |---|---| | [tex]$Cl _2 O _3$[/tex] | | | [tex]$PCl _3$[/tex] | | | [tex]$PCl _5$[/tex] | | | [tex]$Cl _2 O _7$[/tex] | | | [tex]$H _2 O$[/tex] | |

[Answered] What is the formula of the ionic compound $\operatorname{tin}( IV )$ bromide? A. $SnBr _2$ B. $SnBr _4$ C. $Sn _4 Br$ D. $SnB _4$

[Answered] An experimenter attempts to carry out a single replacement reaction between solid copper and a solution of hydrogen fluoride. Which is more reactive - copper or hydrogen? Which of the following equations correctly predicts the products of the reaction? i. $2 Cu _{( s )}+2 HF _{( aq )} \rightarrow F _{2(g)}+2 HCu _{( aq )}$ ii. $Cu _{( s )}+ HF _{( aq )} \rightarrow CuHF _{( s )}$ iii. $2 Cu _{( s )}+2 HF _{( aq )} \rightarrow H _{2(g)}+2 CuF _{( aq )}$ iv. $Cu _{( s )}+ HF _{( aq )} \rightarrow$ no reaction

[Answered] Drag the tiles to the correct boxes to complete the pairs. Match the chemical name of each oxide of phosphorus to its chemical formula. phosphorus monoxide P407 tetraphosphorus heptoxide P205 diphosphorus pentoxide PO diphosphorus tetroxide P₂04

[Answered] Which of the following is NOT a multivalent ion? $Ag^{+}$ $Sb^{5+}$ $Cu^{+}$ $Cr^{3+}$

[Answered] Fill in the systematic names of the following chemical compounds. Note: for compounds containing hydrogen, you may give the common name instead. | molecular formula | name of compound | | :---------------- | :---------------- | | $BI _3$ | | | BP | | | $C _3 S_2$ | | | $CS _2$ | | | $H _2 O$ | |

[Answered] Which element has the lowest electronegativity? A. Ca B. Mg C. Be D. [tex]Sr^{-}$[/tex]

[Answered] The specific heat capacity of a pure substance can be found by dividing the heat needed to change the temperature of a sample of the substance by the mass of the sample and by the change in temperature. The heat capacity of a certain substance has been measured to be $1.66 \frac{J}{ g \cdot{ }^{\circ} C }$. Suppose 149 g of the substance are heated until the temperature of the sample has changed by $42.9^{\circ} C$. Write an equation that will let you calculate the heat $\underline{Q}$ that was needed for this temperature change. Your equation should contain only symbols. Be sure you define each symbol. Your equation: $Q=\square$ Definitions of your symbols: $\square=1.66 \frac{J}{g \cdot{ }^{\circ} C}$ $\square$ - $149 . g$ $\square$ $=42.9^{\circ} C$