Answer:
The process of dissolving is exothermic when more energy is released when water molecules “bond” to the solute than is used to pull the solute apart. Because more energy is released than is used, the molecules of the solution move faster, making the temperature increase.
Project the image Endothermic Dissolving.
The process of dissolving is endothermic when less energy is released when water molecules “bond” to the solute than is used to pull the solute apart. Because less energy is released than is used, the molecules of the solution move more slowly, making the temperature decrease.
Answer:
A) positive; added
Explanation:
Based on the reaction:
2NaHCO3(s) + 129kJ → Na2CO3(s) + H2(g) + CO2(g)
<em>2 moles of NaHCO3 requires 129kJ to produce 1 mole of Na2CO3, 1 mole of H2 and 1 mole of CO2.</em>
<em />
That means, the energy must be added being, thus, an exothermic reaction. The exothermic reactions have ΔH >0.
Thus, right answer is:
A) positive; added
Well, a compound has a total charge of 0. So, it's electrically neutral. Since the X is 3+ and the Y is 3- they add to 0. Meaning no subscripts are necessary. Why don't you try a different combo?
Like:
A^3 and B^1-, to get a 3- charge you need 3xB^1- so the formula is AB3
Does this help?
Answer:
Ion-dipole forces
Explanation:
Na⁺ is a cation, that is, an ion with a positive charge.
NH₃ has polar covalent bonds (due to the difference in electronegativity between nitrogen and hydrogen). According to the VESPR theory, it has a trigonal pyramidal shape with a lone pair. As a consequence, it has a net dipole moment and the molecule is polar.
The intermolecular forces between Na⁺ (ion) and NH₃ (dipole) are ion-dipole forces.
