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Questions in chemistry

[Jawaban] Is aluminum, Al, a representative or transition element?

[Jawaban] Combustion of propane? [tex]C_3 H_3+O_2 \rightarrow H_2 O+CO_2[/tex] Answer Options: Select one of four A. The absorption of heat by the reactants B. The release of heat with the products C. An intermediary transition to butane D. Methane as a secondary product

[Jawaban] What kind of information do unit conversions give? A. Unit conversions give the size of one part of something. B. Unit conversions express a number in terms of moles. C. Unit conversions give a fractional part of a number. D. Unit conversions give an equal amount but with other units.

[Jawaban] Which element would release the most energy while adding an electron to a neutral atom in the gas phase? A. Na B. Al C. Br

[Jawaban] Complete the Nuclear Decay Table: | Decay Type | Mass of particle | Charge of particle | Symbol | |---|---|---|---| | Alpha | 4 | +2 | [tex]$\frac{4}{2} He$[/tex] | | Beta | 0 | -1 | [tex]$-i e$[/tex] | | [?] | 0 | | [tex]$i o \gamma$[/tex] | | Positron Emission | | +1 | | What goes in the missing cells? Choose from the following: Alpha Positron Gamma

[Jawaban] The equation for the pH of a substance is [tex]$pH =-\log \left[ H ^{+}\right]$[/tex], where [tex]$H +$[/tex] is the concentration of hydrogen ions. A basic solution has a pH of 11.2. An acidic solution has a pH of 2.4. What is the approximate difference in the concentration of hydrogen ions between the two solutions? A. [tex]$1.6 \times 10^{-9}$[/tex] B. [tex]$4.0 \times 10^{-3}$[/tex] C. [tex]$6.7 \times 10^{-1}$[/tex] D. [tex]$1.6 \times 10^{11}$[/tex]

[Jawaban] Who is credited with creating the first periodic table? A. Johann Dobereiner B. Henry Moseley C. Dmitri Mendeleev D. John Newlands

[Jawaban] Which will increase the rate of a chemical reaction? A. adding a catalyst B. decreasing the pressure C. decreasing the temperature D. removing a catalyst

[Jawaban] Which element is placed in the same period as ruthenium but has a higher atomic number than it? A. bismuth B. osmium C. silver D. zirconium

[Jawaban] Which substance is a compound? A. water B. gold C. oxygen D. hydrogen