## 2.Mass Percentage and Decimal Rounding:

MaryBanh_2K
Posts: 101
Joined: Wed Sep 18, 2019 12:21 am

### 2.Mass Percentage and Decimal Rounding:

When finding the mass percentage, is there a certain decimal we are supposed to round to?

Wilson 2E
Posts: 100
Joined: Sat Aug 17, 2019 12:18 am

### Re: 2.Mass Percentage and Decimal Rounding:

Most elements on the periodic table are typically given to the hundredths place, so it's best to match that when using percentages so the number of sig figs match up.

Kyle Thorin
Posts: 50
Joined: Sat Aug 24, 2019 12:16 am

### Re: 2.Mass Percentage and Decimal Rounding:

Generally, you're going to want to round to the hundredths so that when you convert to grams you are precise to two decimals, which is usually sufficient for a chemical equation.

charleejohnson1L
Posts: 99
Joined: Fri Aug 30, 2019 12:17 am

### Re: 2.Mass Percentage and Decimal Rounding:

I've been basing my significant figures off of the molar masses indicated on the periodic table. If there is a given mass in the problem, match your percentages to that amount of sig figs. :)

katrinawong3d
Posts: 40
Joined: Sat Aug 17, 2019 12:17 am

### Re: 2.Mass Percentage and Decimal Rounding:

Agreed with the previous answer, I would match the sig figs and round at the end.

Eunice Nguyen 4I
Posts: 100
Joined: Sat Aug 17, 2019 12:17 am

### Re: 2.Mass Percentage and Decimal Rounding:

I typically just match the sig figs to the periodic table values or the numbers given from the question itself. Make sure to never round til the end!!

ClayMeunier1E
Posts: 5
Joined: Fri Aug 09, 2019 12:15 am

### Re: 2.Mass Percentage and Decimal Rounding:

Like other people are saying, it's probably best to round to the hundredths place. Personally, however, I like to round to the thousandths place to increase the likelihood that my percentages will add up to 100.

Anna Chen 1K
Posts: 104
Joined: Thu Jul 25, 2019 12:18 am

### Re: 2.Mass Percentage and Decimal Rounding:

I would just use the exact values on the periodic table values or the given values, not change the amount of sig figs. I usually only round to the hundredths place, if required, in the end.

Charlene Datu 2E
Posts: 62
Joined: Wed Sep 11, 2019 12:16 am

### Re: 2.Mass Percentage and Decimal Rounding:

When finding my answer, I keep the answer to each step to the thousandths place, but I make sure that my final answer follows sig figs (based off of given).

aishwarya_atmakuri
Posts: 101
Joined: Sat Jul 20, 2019 12:15 am

### Re: 2.Mass Percentage and Decimal Rounding:

I would use the same number of significant figures as what is given in the problem.

McKenna_4A
Posts: 115
Joined: Sat Aug 24, 2019 12:18 am

### Re: 2.Mass Percentage and Decimal Rounding:

Just remember sig figs based off the problem. Your periodic table may have extras/not enough.