Determine the concentration of H3O+ to the correct number of significant figures in a solution with each pH. Describe how these calculations show the relationship between the number of digits to the right of the decimal place in pH and the number of significant figures in concentration. pH = 2.50 pH = 2.51 pH = 2.52

Video transcript

Hey everyone today, we're being asked to calculate the concentration of hydro nia miles. When the ph of a solution is 4.83 and we have to make sure we're using the proper number of significant figures. So before anything, I'd like to take note that the ph of the solution is 4.83. And this makes sense because we're actually given the ph instead of the concentration of hydrogen minds to find the ph and this makes our significant figures a little wonky. So let's take a look at that. If the ph is 4.83, right, that means that this, the ph is equal to the negative log of the hydrogen ion concentration, what we're trying to find. And when we're dealing with logarithms, the number of significant figures of the original figure. This concentration that we're trying to solve for will actually be equal to the number of decimal places present in the ph in the final answer. So that means even though there are three digits here, only those after the decimal point are counted. So we have two significant figures. Let's write that down. We have two cig fix. So with that in mind let's go ahead and solve for our hydro um concentration. So as we wrote earlier, the ph is equal to the negative logarithms of the I draw on you my own concentration. So using our laws of logarithms, this must mean that the hydro name ion concentration is equal to tend to the power of the negative ph And we've noted that our ph is 4.83. So this will be 10 to the negative power of sorry, 10 to the power of negative 4.83. And this will give us a value a total value Of 1.479. 1 times 10 To the -5 Moller. However, we need to keep in mind that we still are only able to use to sig figs again, due to the fact that we have to use that logarithms sigfig rule. So if we round this down to two Sig figs, well, that will be rounded to here. And since seven is greater than five, we can round up And this will give us a final answer of 1.5 times 10 To the - Molar. Therefore The concentration of hydro knee um ions when the ph is 4.83, 1.5 times 10 to the -5 Molar. I hope this helps. And I look forward to seeing you on the next one.