Binary mixtures Pchem 1

Aspirin has a higher molar mass compared to salicylic acid, however aspirin melts at a lower temperature than salicylic acid. Provide a brief explanation for this observation. Table 1 Compound: Formula: Salicylic Acid C;H6O3 Aspirin C9H3O4 Molar Mass: 138.12 Melting point: Ka 158-160°C 1.08 x 10³ 180.15 140-142°C 2.72 x 10$ pKa Solubility (g/100ML) 2.99 4.57 0.18 0.25

Which statement best describes the structure of water and its nature as a solvent? O The water molecule is polar and will dissolve polar molecules, such as sugar. O The water molecule is polar and will not dissolve ionic compounds, such as salt. The water molecule is nonpolar and will dissolve polar molecules, such as vinegar. O The water molecule is nonpolar and will dissolve nonpolar molecules, such as oil.

Select the compound that will have the lower equilibrium vapor pressure based on predicted intermolecular forces. pentane (C5H12) phosphorus tribromide

Consider the data in the table. Compound Melting point (°C) AH (kJ/mol) Boiling point (°C) AHap (kJ/mol) HF -83.11 4.577 19.54 25.18 HCI -114.3 1.991 -84.9 17.53 HBr -86.96 2.406 -67.0 19.27 HI -50.91 2.871 -35.38 21.16 Using the data in the table, calculate ASt and AS for HCI. AStn 12.53 J/(K mol) AS. = 93.12 J/(K mol) Determine the entropy change when 3.50 mol HCI(1) freezes at atmospheric pressure. AS = J/K TOOLS

Based on the thermodynamic properties provided for water, determine the amount of energy needed for 2.00 kg of water to go from -16.0 °C to 69.0 °C. Property Melting point Boiling point AHfus AHvap Cp (s) Cp (1) Cp (8) kJ Value 0.0 100.0 6.01 40.67 37.1 75.3 33.6 Units °℃ °C kJ/mol kJ/mol J/mol. °C J/mol • °C J/mol. °C

Based on the thermodynamic properties provided for water, determine the amount of energy needed for 3.20 kg of water to go from -2.00 °C to 78.0 °C. Property Melting point Boiling point AHfus AHvap Cp (s) Cp (1 Cp (8) kJ Value 0.0 100.0 6.01 40.67 37.1 75.3 33.6 Units °℃ °C kJ/mol kJ/mol J/mol • °C J/mol • °C J/mol • °C

MN4.

Two students plan and carry out an investigation to determine if ionic or covalent bonds have stronger intermolecular forces; they use salt and sugar. They collect the following data: Sugar (covalent) white Salt (ionic) white rough, very small grains rough, small grains soluble soluble melts easily does not melt Which of the following tests will most help them to infer the strength of intermolecular forces between ionic and covalent compounds? Color Texture, grain size Solubility in water Melting point 58°F Clear 99+

A substance that does not dissolve well in water. Which of the following can be concluded about the substance?

You leave the house wearing a cotton T-shirt and are surprised by a sudden rainstorm. You notice that the water soaks into the T - shirt whereas it just beads up on your raincoat. In this example, are the adhesive forces or cohesive forces stronger between water and your T - shirt ? Between water and your raincoat ? Explain

● Explain why higher average kinetic energy results in higher vapor pressure in terms of IMFs.

Given the information below, calculate the lattice enthalpy for MX(s), where M is a group 1 metal, and X is a group 17 element (standard state: X2(g)). ΔfH°(MX) = -462 kJ mol−1 ΔsubH°(M) = 127 kJ mol−1 D(X2) = 442 kJ mol−1 IE1(M) = 480 kJ mol−1 Eeg1(X) = -142 kJ mol−1 Express your answer to four significant figures. ΔlattH°(MX) = Answer kJ mol−1