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The subscript on chemical equations tells you how many atoms the elements have. If there is no subscript then there is only 1 atom.
Answer is: the combined ionic bond strength of CrCl₂ and intermolecular forces between water molecules.
When chromium chloride (CrCl₂) is dissolved in water, the temperature of the water increases, heat of the solution is endothermic.
Dissociation of chromium chloride in water: CrCl₂(aq) → Cr²⁺(aq) + 2Cl⁻(aq).
Energy (the lattice energy) is required to pull apart the oppositely charged ions in chromium chloride.
The heat of hydration is liberated energy when the separated ions (in this example chromium cations and chlorine anions) attract polar water molecules.
Because the lattice energy is higher than the heat of the hydration (endothermic reaction), we can conclude that bonds between ions are strong (the electrostatic attraction between oppositely charged ions).
Explanation:
An object in motion <u>stays</u> <u>at</u> motion An object <u>at</u> <u>rest</u> stays at rest unless acted by an <u>external</u> force.
[ Newton's 1st law of motion ]
Answer:
11 electrons
Explanation:
The atomic number of sodium is 11. This tells us that sodium has 11 protons and because it is neutral it has 11 electrons. The mass number of an element tells us the number of protons AND neutrons in an atom (the two particles that have a measurable mass).
When heated, particles vibrate faster, thus increasing the distance between one another. The distance between these particles results in changes of state. Therefore, increased molecular motion results in expansion of an object. This works vice versa for cooling. As the vibrations slow down, the particles become closer together. This results in contraction.
