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Questions in chemistry

📝 Answered - Which element is a transition metal? oxygen, O uranium, U neon, Ne cobalt, Co

📝 Answered - Which is a substance that is made up of only one type of atom? A. compound B. element C. solution D. mixture

📝 Answered - An electric device delivers a current of [tex]$15.0 A$[/tex] for 30 seconds. How many electrons flow through it?

📝 Answered - Naiñe. Formula. 2. Write a balanced equation for the reaction between the following solutions below: a. [tex]HCl ( aq )+ MgO ( s ) \longrightarrow[/tex]: + b. [tex]HNO _3( aq )+ Ca ( OH )_2( aq ) \longrightarrow[/tex] + c. [tex]H _2 SO _4( aq )+ KOH ( aq ) \longrightarrow[/tex] + 3. From the following neutralization reaction, write a. a balanced equation b. an ionic equation and c. a net ionic equation for the reaction not involving the spectator ions. 4. [tex]HNO _3+ NH _4 OH \longrightarrow[/tex]

📝 Answered - Constants for water \begin{tabular}{|l|l|} \hline$\Delta H_{\text {vap }}$ & $40.65 kJ / mol$ \\ \hline$\Delta H_{\text {f }}$ & $-285.83 kJ / mol$ \\ \hline$\Delta H_{\text {fuslon }}$ & $6.03 kJ / mol$ \\ \hline specific heat & $4.186 J / g ^{\circ} C$ \\ \hline molar mass & 18.02 g \\ \hline \end{tabular} How much energy is released when 6.0 g of water is condensed from water vapor? A. $6.0 g \times 1 mol / 18.02 g \times 6.03 kJ / mol$ B. $6.0 g \times 1 mol / 18.02 g \times 40.65 kJ / mol$ C. $6.0 g \times 1 mol / 18.02 g \times 4.186 kJ / mol$ D. $6.0 g \times 1 mol / 18.02 g \times(-285.83 kJ / mol )$

📝 Answered - T1.15 Which ONE of the following statements is TRUE for an oxidising agent? A) It gains electrons. B) It causes another species in the reaction to be reduced. C) Its oxidation number does not change during a chemical reaction. D) Its oxidation number increases during a chemical reaction. edu1.6 Which ONE of the following metals will reduce Cd2+(aq) to Cd(s), but will NOT reduce Mn2+(aq) to Mn(s)? A) Zn B) Ag C) Ni D) Mg

📝 Answered - Propane $(C_3H_8(g), \Delta H_f = -103.8 \text{ kJ/mol})$ reacts with oxygen to produce carbon dioxide $(CO_2, \Delta H_f = -393.5 \text{ kJ/mol})$ and water $(H_2O, \Delta H_f = -241.82 \text{ kJ/mol})$ according to the equation below: $C_3H_8(g) + 5O_2(g) \rightarrow 3CO_2(g) + 4H_2O(g)$ What is the enthalpy of combustion (per mole) of $C_3H_8(g)$? Use $\Delta H_{\text{rxn}} = \sum(\Delta H_{\text{f, products}}) - \sum(\Delta H_{\text{f, reactants}})$. A. -2,044.0 kJ/mol B. -531.5 kJ/mol C. 531.5 kJ/mol D. 2,044.0 kJ/mol

📝 Answered - Fill in the blanks. 11. Soy sauce and water is (a uniform / not a uniform) mixture because ____. 12. Peas and carrots (a uniform) mixture because ____. 13. Glue and water is (a uniform / non-uniform) mixture because ____. 14. Spaghetti and meatballs is (a homogeneous / heterogeneous mixture) because ____. 15. Salt and water is (a homogeneous / heterogeneous mixture) because ____. Classify the following mixture as homogeneous or heterogeneous. 16. Vegetable 17. Halo-halo 18. Air 19. Table salt and water 20. Concrete materials

📝 Answered - I. Concentration II. Temperature of reactants III. Surface area of reactants Please mark 1 answer: A. I and III only B. I and II only C. I, II and III D. II and III only 3A (aq) -> 2B (aq) + C (aq), the decomposition of compound A at 300 K in a solution with constant volume can be followed by monitoring the concentration of A. Initially, the concentration of A is 2.94 mol dm⁻³, and after 1.3 min, it is reduced to 1.76 mol dm⁻³. Calculate the rate of the reaction. Please mark 1 answer: A. 5 x 10³ mol dm⁻³ s⁻¹ B. 0.0504 mol dm⁻³ s⁻¹ C. 3 x 10² mol dm⁻³ s⁻¹ D. 3.8 x 10³ mol dm⁻³ s⁻¹

📝 Answered - Since kerosene is a "combustible", it should have a flashpoint ___ degrees Fahrenheit. A. of less than 32 B. of less than 100 C. between 100 and 200 D. of more than 200