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1 year ago

Which statement best compares the energy involved in melting with the energy involved in boiling for a given liquid?

Chemistry

2 answers:

Soloha48 [4]1 year ago

4 0

C its c trust me i just took the quiz

ruslelena [56]1 year ago

3 0

Answer is: Energy is added to the particles in each change, but boiling requires more energy than melting because the attractions must be completely overcome.

For example, melting point of the water is 0°C and boiling point of the water is 100°C.

While melting, solid water (ice) is changed into liquid water.

While boiling, liquid water is changed into gaseous water (water steam).

Between molecules of water there are hydrogen bonds, which must be brake so water can evaporate.

Hydrogen bond is an electrostatic attraction between two polar groups in which one group has hydrogen atom (H) and another group has highly electronegative atom such as nitrogen (like in this molecule), oxygen (O) or fluorine (F).

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What is the mass of a sample of NH3 containing 6.3 × 1024 molecules of NH3?

quester [9]

Answer:

178 grams

Explanation:

It is known that 1.0 mole of a compound contains Avogadro's number of molecules (6.022 x 10²³).

Using cross multiplication:

1.0 mol contains → 6.022 x 10²³ molecules.

??? mol contains → 6.3 x 10²⁴ molecules.

∴ The no. of moles of (6.3 x 10²⁴ molecules) of NH₃ = (1.0 mol)(6.3 x 10²⁴ molecules)/(6.022 x 10²³ molecules) = 10.46 mol.

∴ The no. of grams of NH₃ present = no. of moles x molar mass = (10.46 mol)(17.0 g/mol) = 177.8 g ≅ 178 g.

7 0

1 year ago

Hydrogen, a potential future fuel, can be produced from carbon (from coal) and steam by the following reaction: C(s)+2H2O(g)→2H2

madam [21]

The question is incomplete , complete question is:

Hydrogen, a potential future fuel, can be produced from carbon (from coal) and steam by the following reaction:

$C(s)+ 2 H_2O(g)\rightarrow 2H_2(g)+CO_2(g).\Delta H=?$

Note that the average bond energy for the breaking of a bond in CO2 is 799 kJ/mol. Use average bond energies to calculate ΔH of reaction for this reaction.

Answer:

The ΔH of the reaction is -626 kJ/mol.

Explanation:

$C(s)+ 2 H_2O(g)\rightarrow 2H_2(g)+CO_2(g).\Delta H=?$

We are given with:

$\Delta H_{H-O}=459 kJ/mol$

$\Delta H_{H-H}=432 kJ/mol$

$\Delta H_{C=O}=799 kJ/mol$

ΔH = (Energies required to break bonds on reactant side) - (Energies released on formation of bonds on product side)

$\Delta H=(4\times \Delta H_{O-H})-(2\times \Delta H_{H-H}+2\times\Delta H_{C=O})$

$=(4\times 459 kJ/mol)-(2\times 432 kJ/mol+2\times 799 kJ/mol$

$\Delta H=-626 kJ/mol$

The ΔH of the reaction is -626 kJ/mol.

5 0

2 years ago

2. Which of the following diagrams accurately represents the use of gases in both cellular respiration

sesenic [268]

Answer:

In algae or any other photosynthetic organism, there is the internalization of carbon dioxide gas in the reaction with water in the presence of sunlight to produce sugar molecules and oxygen gas in the atmosphere. So, photosynthesis is the process that releases or produces oxygen gas.

In cellular respiration (aerobic) the product of photosynthesis, glucose molecules, and oxygen react to produce the energy and releases carbon dioxide and water as byproducts.

7 0

1 year ago

Read 2 more answers

Using the equations 2 Sr(s) + O₂ (g) → 2 SrO (s) ∆H° = -1184 kJ/mol SrO (s) + CO₂ (g) → SrCO₃ (s) ∆H° = -234 kJ/mol CO₂ (g) → C(

kkurt [141]

Answer: The $\Delta H^o_{rxn}$ for the reaction is 72 kJ.

Explanation:

Hess’s law of constant heat summation states that the amount of heat absorbed or evolved in a given chemical equation remains the same whether the process occurs in one step or several steps.

According to this law, the chemical equation is treated as ordinary algebraic expressions and can be added or subtracted to yield the required equation. This means that the enthalpy change of the overall reaction is equal to the sum of the enthalpy changes of the intermediate reactions.

The given chemical reaction follows:

$2SrCO_3(s)\rightarrow 2Sr(s)+2C(s)+3O_2(g)$ $\Delta H^o_{rxn}=?$