Química preguntas y respuestas

Calculate the volume of 2.4 mol of nitrogen gas at \( 28^{\circ} \mathrm{C} \) and 110 kPa pressure.

Cercise 1-9 A sample of gas has a volume of 4.50 L at a pressure of 800 mmHg . The volume of the gas is increased to 8.00 L (the temperature remains constant). What is the pressure of the gas now?

Which of the following statements is true regarding the conservation of mass? Mass can be created during a chemical reaction. Mass can be destroyed during a chemical reaction. Mass is neither created nor destroyed during a chemical reaction.

How much heat is required to raise the temperature of 100.0 mL of water from \( 12.00^{\circ} \mathrm{C} \) to \( 18.00^{\circ} \mathrm{C} \) ? - Round the answer to three significant figures, - The specific heat capacity of water is \( 4.184 \frac{\mathrm{~J}}{\mathrm{~g}^{\circ} \mathrm{C}} \). The density of water is \( 1.000 \frac{\mathrm{~g}}{\mathrm{~mL}} \),

6.1 Methane gas is one of the hydrocarbons that is used as a source of fuels worldwide. When methane reacts with oxygen, water and carbon dioxide are formed. Atoms of water molecules in the above reaction are bonded by a covalent bond. 6.1.1 Define the term covalent bond. 6.1.2 Write down the balanced chemical equation. Consider the following balanced equation of a chemical reaction. 6.2.1 The chemical formula of compound X in the above reaction 6.2.2 The type of bond that exists in compound \( X \) 6.2.3 The Lewis structure of compound \( X \) [9] QUESTION 7 Study the illustrations of the diagrams below and answer the questions which follow.

A 45.0 g piece of metal with specific heat \( 0.450 \frac{\mathrm{~J}}{\mathrm{~g}^{\circ} \mathrm{C}} \) and at \( 115^{\circ} \mathrm{C} \) is placed in \( 200 . \mathrm{g} \) of water at \( 25.0^{\circ} \mathrm{C} \). What will be the final temperature of the water? Select the correct answer below: \( 2.10^{\circ} \mathrm{C} \) \( 29.8^{\circ} \mathrm{C} \) \( 88.4^{\circ} \mathrm{C} \) \( 27.1^{\circ} \mathrm{C} \)

Calculate the cell potential for the galvanic cell in which the given reaction occurs at \( 25^{\circ} \mathrm{C} \), given that \( \left[\mathrm{Sn}^{2+}\right]=0.0673 \mathrm{M} \), \( \mathrm{Sn}^{2+}(\mathrm{aq})+2 \mathrm{Co}^{3+}(\mathrm{aq}) \rightleftharpoons \mathrm{Sn}^{4+}(\mathrm{aq})+2 \mathrm{Co}^{2+}(\mathrm{aq}) \)

Calculate the potential of the electrochemical cell and determine if it is spontaneous as written at \( 25^{\circ} \mathrm{C} \). \[ \mathrm{Pt}(\mathrm{s})\left|\mathrm{Sn}^{2+}(0.0062 \mathrm{M}), \mathrm{Sn}^{4+}(0.11 \mathrm{M}) \| \mathrm{Fe}^{3+}(0.11 \mathrm{M}), \mathrm{Fe}^{2+}(0.0018 \mathrm{M})\right| \mathrm{Pt}(\mathrm{s}) \] \( E_{\mathrm{Sn}^{4+} / \mathrm{Sn}^{2+}}^{\circ}=0.154 \mathrm{~V} \quad E_{\mathrm{Fe}^{3+} / \mathrm{Fe}^{2+}}^{\circ}=0.771 \mathrm{~V} \)

Calculate the potential of the electrochemical cell and determine if it is spontaneous as written at \( 25^{\circ} \mathrm{C} \). \( \begin{array}{l}\mathrm{Cu}(\mathrm{s})\left|\mathrm{Cu}^{2+}(0.13 \mathrm{M}) \| \mathrm{Fe}^{2+}(0.0017 \mathrm{M})\right| \mathrm{Fe}(\mathrm{s}) \\ E_{\mathrm{Cu}^{2+} / \mathrm{Cu}}^{\circ}=0.339 \mathrm{~V} \quad E_{\mathrm{Fe}^{2+} / \mathrm{Fe}}^{\circ}=-0.440 \mathrm{~V}\end{array} \)

What is the mass in grams of a sample of water when the temperature drops from \( 75.00^{\circ} \mathrm{C} \) to \( 56.00^{\circ} \mathrm{C} \) and 800.0 J of energy are lost? - Enter the answer with four significant figures. - Use \( 4.184 \frac{\mathrm{~J}}{\mathrm{~g}^{\circ} \mathrm{C}} \) for the specific heat of water. Provide your answer below: