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Questions in chemistry

[Terjawab] What is the smallest unit of an ionic bond? A. a molecule B. a formula unit C. an atom

[Terjawab] Consider the following data on some weak acids and weak bases: Use this data to rank the following solutions in order of increasing pH. In other words, select a '1' next to the solution that will have the lowest pH, a '2 the solution that will have the next lowest pH, and so on.

[Terjawab] Type the correct answer in the box. The solubility of calcium carbonate is [tex]$14 \frac{\text { milligrams }}{\text { liter }}$[/tex]. This rate means that 14 milligrams of calcium carbonate can dissolve in 1 liter of water. How much water would be required to fully dissolve 11 grams of calcium carbonate? Express your answer to the correct number of significant figures. One milligram is equal to 0.001 grams. It would take $\square$ liters of water to fully dissolve 11 grams of calcium carbonate.

[Terjawab] A. 125.6 kJ B. 3440 kJ C. 1720 kJ D. 10.4 kJ

[Terjawab] A cube of iron $\left(C_p=0.450 J / g \cdot{ }^{\circ} C \right)$ with a mass of 55.8 g is heated from $25.0^{\circ} C$ to $49.0^{\circ} C$. How much heat is required for this process? Round your answer to three significant figures. Use the formula $q=m C_y \Delta T$.

[Terjawab] Rolf prepares four solutions using different solutes as shown in the table below. | Solution | Preparation | Solubility of the solutes | |---|---|---| | A | Rolf added 20 g of solute to 100 g of water and mixed the solution. | The solute in solution A has a solubility of [tex]$37 g / 100 g H _2 O$[/tex] at [tex]$20^{\circ} C$[/tex]. | | B | Rolf added 10 g of solute to 100 g of water and mixed the solution. | The solute in solution B has a solubility of [tex]$10 g / 100 g H _2 O$[/tex] at [tex]$20^{\circ} C$[/tex]. | | C | Rolf added 65 g of solute to 100 g of water, mixed the solution, and then heated the solution. | The solute in solution C has a solubility of [tex]$32 g / 100 g H _2 O$[/tex] at [tex]$20^{\circ} C$[/tex]. | | D | Rolf added 7 g of solute to 100 g of water, mixed the solution, and then heated the solution. | The solute in solution D has a solubility of [tex]$4 g / 10 A H _2 O$[/tex] at [tex]$20^{\circ} C$[/tex]. | Which solution is unsaturated? A. Solution A B. Solution B C. Solution C D. Solution D

[Terjawab] A sample of an unknown substance has a mass of 0.158 kg. If [tex]$2,510.0 J$[/tex] of heat is required to heat the substance from [tex]$32.0^{\circ} C$[/tex] to [tex]$61.0^{\circ} C$[/tex], what is the specific heat of the substance? Use [tex]$q=m C_p \Delta T$[/tex]. A. [tex]$0.171 J /\left( g _{ i }{ }^{\circ} C \right)$[/tex] B. [tex]$0.548 J /\left( g _{ i }{ }^{\circ} C \right)$[/tex] C. [tex]$15.9 J /\left( g _{ i }{ }^{\circ} C \right)$[/tex] D. [tex]$86.6 J /\left( g _{ i }{ }^{\circ} C \right)$[/tex]

[Terjawab] Give 5 environmental impacts of mining.

[Terjawab] Which equation shows how to calculate how many grams $(g)$ of KCl would be produced from 4 mol KOH? The balanced reaction is: $MgCl_2+2 KOH \rightarrow Mg(OH)_2+2 KCl$ A. $\frac{4 mol KOH }{1} \times \frac{1 mol KCl }{2 mol KOH } \times \frac{74.55 g KCl }{1 mol KCl }$ B. $\frac{4 mol KOH }{1} \times \frac{2 mol KCl }{1 mol KOH } \times \frac{74.55 g KCl }{1 mol KCl }$ C. $\frac{4 mol KOH }{1} \times \frac{2 mol KCl }{2 mol KOH } \times \frac{74.55 g KCl }{1 mol KCl }$ D. $\frac{4 mol KOH }{1} \times \frac{1 mol KOH }{1 mol KCl } \times \frac{74.55 g KCl }{1 mol KCl }$

[Terjawab] Consider the following intermediate chemical equations: [tex] \begin{array}{ll} P_4(s)+6 Cl_2(g) \rightarrow 4 PCl_3(g) & \Delta H_1=-2,439 kJ \\ 4 PCl_5(g) \rightarrow P_4(s)+10 Cl_2(g) & \Delta H_2=3,438 kJ \end{array} [/tex] What is the enthalpy of the overall chemical reaction [tex]PCl _5(g) \rightarrow PCl _3(g)+ Cl _2(g)[/tex]? A. -999 kJ B. -250 kJ C. 250 kJ D. 999 kJ