Based on the data given in this question, the statement that shows a correct interpretation of the chemical reactions is as follows: reaction A was exothermic and reaction B was endothermic.
<h3>What are endothermic and exothermic reactions?</h3>
Endothermic reaction is a chemical reaction that absorbs heat energy from its surroundings while exothermic reaction is a reaction that releases energy in the form of heat.
Endothermic reactions leave their surroundings cooler while exothermic reactions leave their surroundings hotter.
According to this question, the initial and final temperatures of two reactions are given as follows:
- Reaction A: 25.1°C and 30.2°C
- Reaction B: 25.1°C and 20.0°C
From the above data, reaction A was exothermic because it increased the surrounding temperature and reaction B was endothermic because it reduced the surrounding's temperature.
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Answer:
Its atomic mass increases by 1
An isotope of that element is fotmed with mass differences by 1
Explanation:
The answer would be .5 mols because you take the total amount of grams, which is 20, and you had up the molar mass of sodium hydroxide, which would be 40. After you have this you would set this up as a stochiometry equation. With 1 mol on top you dived 20/40 to cancel out your grams. This leaves you with .5 mols
1. The reactivity among the alkali metals increases as you go down the group due to the decrease in the effective nuclear charge from the increased shielding by the greater number of electrons. The greater the atomic number, the weaker the hold on the valence electron the nucleus has, and the more easily the element can lose the electron. Conversely, the lower the atomic number, the greater pull the nucleus has on the valence electron, and the less readily would the element be able to lose the electron (relatively speaking). Thus, in the first set comprising group I elements, sodium (Na) would be the least likely to lose its valence electron (and, for that matter, its core electrons).
2. The elements in this set are the group II alkaline earth metals, and they follow the same trend as the alkali metals. Of the elements here, beryllium (Be) would have the highest effective nuclear charge, and so it would be the least likely to lose its valence electrons. In fact, beryllium has a tendency not to lose (or gain) electrons, i.e., ionize, at all; it is unique among its congeners in that it tends to form covalent bonds.
3. While the alkali and alkaline earth metals would lose electrons to attain a noble gas configuration, the group VIIA halogens, as we have here, would need to gain a valence electron for an full octet. The trends in the group I and II elements are turned on their head for the halogens: The smaller the atomic number, the less shielding, and so the greater the pull by the nucleus to gain a valence electron. And as the atomic number increases (such as when you go down the group), the more shielding there is, the weaker the effective nuclear charge, and the lesser the tendency to gain a valence electron. Bromine (Br) has the largest atomic number among the halogens in this set, so an electron would feel the smallest pull from a bromine atom; bromine would thus be the least likely here to gain a valence electron.
4. The pattern for the elements in this set (the group VI chalcogens) generally follows that of the halogens. The greater the atomic number, the weaker the pull of the nucleus, and so the lesser the tendency to gain electrons. Tellurium (Te) has the highest atomic number among the elements in the set, and so it would be the least likely to gain electrons.
Answer: Too much base was added
i guessed
Explanation:
