Given what we know, we can confirm that as with any experiment, the control variable will be the one that through each trial of the experiment, no matter how many times it is performed, stays constant.
<h3>What is a controlled variable?</h3>
- A variable that remains constant through an experiment.
- They are used to compare results to the normal condition.
- They are also used to isolate the changes to one factor at a time and thus know its exact effects on the outcome.
- This increases the accuracy of the data and the subsequent conclusion.
Therefore, we can confirm that if a variable stays constant through each phase and trial of an experiment, it is considered to be a controlled variable and is useful in order to increase the accuracy of the conclusion.
To learn more about control variables visit:
brainly.com/question/17555102?referrer=searchResults
Answer:
Option 3. The catalyst does not affect the enthalpy change (
) of a reaction.
Explanation:
As its name suggests, the enthalpy change of a reaction (
) is the difference between the enthalpy of the products and the reactants.
On the other hand, a catalyst speeds up a reaction because it provides an alternative reaction pathway from the reactants to the products.
In effect, a catalyst reduces the activation energy of the reaction in both directions. The reactants and products of the reaction won't change. As a result, the difference in their enthalpies won't change, either. That's the same as saying that the enthalpy change
of the reaction would stay the same.
Refer to an energy profile diagram. Enthalpy change of the reaction
measures the difference between the two horizontal sections. Indeed, the catalyst lowered the height of the peak. However, that did not change the height of each horizontal section or the difference between them. Hence, the enthalpy change of the reaction stayed the same.
The given concentration of boric acid = 0.0500 M
Required volume of the solution = 2 L
Molarity is the moles of solute present per liter solution. So 0.0500 M boric acid has 0.0500 mol boric acid present in 1 L solution.
Calculating the moles of 0.0500 M boric acid present in 2 L solution:

Converting moles of boric acid to mass:

Therefore, 6.183 g boric acid when dissolved and made up to 2 L with distilled water gives 0.0500 M solution.
Answer:
The number of neutrons is entirely dependent on the Mass number of the particular atom. The standard mass for potassium is 39.
Potassium is element number 19, so it has 19 protons and 19 electrons in the neutral atom. It has therefore 39-19 = 20 Neutrons.
Explanation:
The correct answer is decomposers.