First consider and take note of the following:
1. When 2 or more finite amounts of substances are mix together (with different temperature) the final temperature is never equivalent to the initial temperature of any of the substances involved.
2. The substances meet at an equilibrium temperature.
3. Heat transfers from a higher temperature to a lower temperature.
Only choice (3) satisfies the conditions.
The molar mass of NaCl is 23 + 35.5 = 58.5 g/mol, so the mass of the sample ia 0.78 × 58.5 = 45.63 g.
Answer:
Potassium iodide increases the decomposition rate of hydrogen peroxide.
Explanation:
Potassium iodide increases the decomposition rate of hydrogen peroxide because potassium iodide act as a catalyst. A catalyst speed up the process of chemical reaction without reacting with the molecules present in reaction. If the potassium iodide is not present as a catalyst for the decomposition of hydrogen peroxide then the decomposition of hydrogen peroxide takes too much time because the catalyst is absent that speed up the reaction.
The temperature of the air, pavement, and the type of ice-melt compound used will affect the rate at which the ice melts. There are many different ice-melt compounds available from traditional rock salt (sodium chloride) to ice-melt pellets (calcium chloride).
The element that will have the lowest electronegativity is an element with a small number of valence electrons and a large atomic radius.
Electronegativity of an element is the ability or power of that element in a molecule to attract electrons to its Valence electrons. The following are the properties of electronegativity:
- It increases across a period from left to right of the periodic table,
- It decreases down the periodic table groups
- Group 1 elements are the least (lowest) electronegative elements. These elements have the lowest valence electrons with a large atomic radius.
- Group 7 elements are the most electronegative elements.
Atomic radius of elements increase down a group because of a progressive increase in the number of shells occupied by electrons which increases the size. But it decreases across a period because electrons are accommodated within the same shell leading to greater attraction by the protons in the nucleus.
Learn more about electronegativity of elements here:
brainly.com/question/20348681
