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Questions in chemistry

[Terjawab] GAS-EVOLUTION REACTIONS 7) [tex]HCl (aq)[/tex] and [tex]Na_2S(aq)[/tex] [tex]2 HCl (aq) + Na_2S(aq) \rightarrow H_2S_1(g)[/tex] Molecular Equation Complete Ionic Equation Net Ionic Equation Spectator Ions

[Terjawab] Consider the following intermediate chemical equations: [tex]$\begin{array}{l} CH_4(g)+2 O_2(g) \rightarrow CO_2(g)+2 H_2 O(g) \ 2 H_2 O(g) \rightarrow 2 H_2 O(l) \end{array}$[/tex] Which overall chemical equation is obtained by combining these intermediate equations? A. [tex]$CH _4(g)+2 O _2(g) \rightarrow CO _2(g)+2 H _2 O ( I )$[/tex] B. [tex]$CH _4(g)+2 O _2(g) \rightarrow CO _2(g)+2 H _2 O ( g )$[/tex] C. [tex]$CH _4(g)+2 O _2(g) \rightarrow CO _2(g)+4 H _2 O ( g )+2 H _2 O ( l )$[/tex] D. [tex]$CH _4(g)+2 O _2(g) \rightarrow CO _2(g)+ BH _2 O ( g )$[/tex]

[Terjawab] How is the equilibrium constant of a reaction determined? The molarity of products is multiplied by the molarity of reactants.

[Terjawab] The number of valence electrons in an element with electron configuration [tex]$1 s^2 2 s^2 2 p^6 3 s^2 3 p^4$[/tex] is A. 6 B. 8 C. 4 D. 2 E. 16

[Terjawab] Which statement is true about this reaction? N+H-150 A. It is a practical source of energy on Earth. B. It occurs only outside the solar system. C. Its product is heavier than each of its reactants. D. It shows the critical mass of an element.

[Terjawab] Q6. Rahim found three old chemical bottles in the storeroom of his house. He wants to test whether these chemicals are acidic, basic or neutral. Which of the following indicators should he use to test the chemicals? (a) Beetroot juice (b) Turmeric strip (c) Vanilla essence (d) China rose

[Terjawab] Ammonia, [tex]$NH _3(\Delta H_1=-45.9 kJ)$[/tex], reacts with oxygen to produce water [tex]$\left(\Delta H_1=-241.8 kJ\right)$[/tex] and nitric oxide, [tex]$NO \left(\Delta H_1=\right.$ 91.3 kJ )[/tex], in the following reaction: [tex]$4 NH_3(g)+5 O_2(g) \rightarrow 6 H_2 O(g)+4 NO(g)$[/tex] What is the enthalpy change for this reaction? Use [tex]$\Delta H_{\text {rxn }}=\sum\left(\Delta H_{\text {t, products }}\right)-\sum\left(\Delta H_{\text {f, reactants }}\right)$[/tex]. A. -902 kJ B. -104.6 kJ C. 104.6 kJ D. 900.8 kJ

[Terjawab] What is the mass percent of oxygen $( O )$ in $SO _2$ ? A. $\frac{(16.0 g+16 g)(6.02 \times 10^{23})}{100 g}$ B. $\frac{32.1 g}{16.0 g+16.0 g} \times 100 \%$ C. $\frac{16.0 g}{(32.1 g+16.0 g+16.0 g)} \times 100 \%$ D. $\frac{(16.0 g+16.0 g)}{(32.1 g+16.0 g+16.0 g)} \times 100 \%$

[Terjawab] How does solubility for a solid vary with temperature? Some sample data similar to the lab is given below. Oxygen in Water | Temperature (°C) | Concentration (mg solute/mL solvent) | |---|---| | 5 | 0.12 | | 15 | 0.10 | | 25 | 0.08 | | 45 | 0.06 | Sucrose in Water | Temperature (°C) | Concentration (g solute/ml solvent) | |---|---| | 10 | 1.95 | | 30 | 2.20 | | 50 | 2.60 | | 70 | 3.20 |

[Terjawab] 1. The smallest independent particle that makes up all the matter. 2. Substances that can flow from one place to another. 3. The liquid obtained by dissolving a solute in a solvent. 4. The process by which a liquid changes into a solid on cooling. 5. State of matter having loosely packed molecules.