VincenTragosta - Tanya, Jawab, dan Belajar Tanpa Batas Logo

Questions in chemistry

[Terjawab] Through chemical weathering, even hard rocks can produce what? A. sediment B. limestone C. kaolin D. minerals

[Terjawab] 3. In one molal solution that contains 0.5 mol of solute, there is (A) 500 g of solvent (B) 100 mL of solvent (C) 1000 g of solvent (D) 500 mL of solvent 4. The mixture that forms maximum boiling azeotrope at a specific composition is (A) Water + Nitric acid (B) Ethanol + water

[Terjawab] Ammonia $\left( NH _3(g), \Delta H_{ f }=-45.9 kJ / mol \right)$ reacts with oxygen to produce nitrogen and water $\left( H _2 O ( g ), \Delta H_{ f }=-241.8\right.$ $kJ / mol$ ) according to the equation below. $4 NH_3(g)+3 O_2(g) \rightarrow 2 N_2(g)+6 H_2 O(g)$ What is the enthalpy of the reaction? Use $\Delta H_{\text {rxn }}=\sum\left(\Delta H_{\text {f,products }}\right)-\sum\left(\Delta H_{f, \text { reactants }}\right)$. A. -3,572.1 kJ B. -1,267.2 kJ C. 1,267.2 kJ D. 3,572.1 kJ

[Terjawab] | Name of People/Scientist | Element's Name | Symbol | |---|---|---| | 1. Neils Bohr | Bohrium | Bh | | 2. Albert Einstein | Einsteinium | Es | | 3. Ernest Lawrence | Lawrencium | Lr | | 4. Glenn T. Seaborg | Seaborgium | Sg | | 5. Dmitri Mendeleev | Mendelevium | Md | | 6. Marie and Pierre Curie | Curium | Cm | | 7. Enrico Fermi | Fermium | Fm | | 8. Ernest Rutherford | Rutherfordium | Rf | | 9. Alfred Nobel | Nobelium | No | | 10. Nicolas Copernicus | Copernicium | Cn |

[Terjawab] Juliet started working with a radioactive substance. In 1997, she started with 200 g. When she measured again in 2002, she had 100 g left. In 2007, she had 50 g. | Radioactive isotope | Half-life | |---|---| | Rubidium-91 | 58.4 seconds | | lodine-131 | 8 days | | Cobalt-60 | 5 years | | Carbon-14 | 5730 years | | Cesium-135 | $2.3 \times 10^6$ years | | Uranium-238 | $4.5 \times 10^9$ years | Which substance is she most likely measuring? A. rubidium-91 B. iodine-131 C. cobalt-60 D. carbon-14

[Terjawab] What causes atoms to react with each other? A. A state change B. A chemical equation C. A chemical reaction D. A physical change

[Terjawab] A student separates salt from a mixture of salt and sand. What is the correct order of steps for the student to take? A) filter -> evaporate -> shake with water B) filter -> shake with water -> evaporate C) shake with water -> evaporate -> filter D) shake with water -> filter -> evaporate

[Terjawab] Manganese dioxide [tex]$\left( MnO _2(s), \Delta H_{ f }=-520.0 kJ\right)$[/tex] reacts with aluminum to form aluminum oxide [tex]$\left( Al _2 O _3(s), \Delta H_{ f }=-\right.$[/tex] [tex]$1699.8 kJ / mol$[/tex]) and manganese according to the equation below. [tex]$3 MnO_2(s)+4 Ar(s) \rightarrow 2 Al_2 O_3(g)+3 Mn(s)$[/tex] What is the enthalpy of the reaction? Use [tex]$\Delta H_{r \times n}=\sum\left(\Delta H_{\text {teproducts }}\right)-\sum\left(\Delta H_{\text {tereatants }}\right)$[/tex]

[Terjawab] In the combustion of propane, $C_3H_8$, 32 g of $O_2$ is needed to form 10 g of $H_2O$. What are the theoretical yield and percentage yield of $H_2O$? ($C = 12, O = 16, H = 1$) $C_3H_8(g) + 5O_2(g) \longrightarrow 3CO_2(g) + 4H_2O(1)$

[Terjawab] 1. From the following ionic equations below, put a tick (✓) if there is a reaction taking place and an x if there is no reaction taking place. a. [tex]Zn ^{2+}( aq )+ Fe ( s ) \longrightarrow Fe ^{2+}(\frac{ aq }{ a })+ Zn ( s )[/tex] b. [tex]Mg ^{2+}( aq )+ Zn ( s ) \longrightarrow Zn ^{2+}( aq )+ Mg ( s )[/tex] c. [tex]Fe ^{2+}( aq )+ Zn ( s ) \longrightarrow Zn ^{2+}( aq )+ Fe ( s )[/tex] d. [tex]Pn ^{2+}( aq )+ Cu ( s ) \longrightarrow Cu ^{2+}( aqu ) ! Pu ( s )[/tex] e. [tex]Cu ^{2+}( aq )+ Fe ( s ) \longrightarrow Fe ^{2+}( aq )+ Cu ( s )[/tex] 2. Define spectator ion.