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# Tag Info

## Hot answers tagged significant-figures

13 votes
Accepted

5 votes

### Is precision measured by significant digits in chemistry?

The single measured values provided by 3 different tools gives us just a hint about possible accuracy or precision of the tools. The tool providing the value 1.39 is probably, but not necessarily ...
• 42.2k
4 votes

### Significant Figures

Significant figures are a sloppy method for doing error propagation. The point with significant figures is to maintain "reasonable" precision in the answer. Ideally you'd assume that the ...
• 22.3k
4 votes

### Why do significant figure rules contradict each other?

Bear in mind the significant digit rules are just simplifications of the rules of absolute (+, -) and relative (*,/) variance propagation. The rule of significant digit numbers for summing is for 2 ...
• 42.2k
4 votes

### Significant figures and accuracy

Both method 1 and method 2 are wrong. The concept of useless significant figures should be wiped out from school curricula and replaced with proper statistics. This significant figures and concept of ...
• 41k
4 votes

### Number of significant figures to use in reporting the concentration of the titrand in acid-base titration

You said that you have done seven titrations, i.e., you have the set of concentrations $\{c_1, c_2, \ldots, c_7\}$. I offer you the following standard statistical approach to inform your concentration ...
• 3,436
3 votes

### Am I Using the Correct Number of Significant Figures (Heat Problem)?

This is sort of tricky, but I'd say that neither 10.8 nor 11 is right! You got $$Q_1 = 9.7\bar22753346\ \mathrm{kcal}$$ which you rounded to $9.72\ \mathrm{ kcal}$. The bar over the first two ...
• 22.3k
3 votes

### Chemistry 101 - significant figures

Truthfully this seems like a poor question. Either (A) or (B) could be argued. (A) The ruler is marked in cm, so the measurement can only be made guaranteed to the cm. You can try to interpolate to ...
• 22.3k
3 votes

### Significant Figures

As an error is not explicitly given and as your first number is $7.195$ g this means that the absolute error bound implied is 0.0005, which is to say that the error (uncertainty) is in the decimal ...
• 30.6k
3 votes
Accepted

### Uncertainty of Atomic Mass

First of all it is important to realize that the number you quote is not the atomic mass of magnesium, but the avarage (molar) mass of all naturally occuring isotopes. If you visit the wikipedia page ...
• 2,396
3 votes

### What do final zeros to the right of decimal point indicate?

The zeros to the right of the decimal point denotes the expected precision of a measurement. Thus a value of 2.0 indicates that the the measurement falls in the interval [1.95,2.05[. The value 2.00 ...
3 votes

### Percent error and significant figures?

Actually the % error is calculated as: $\frac{\text{experimental} - \text{actual}}{\text{actual}}\cdot100\%$ That way if experimental < actual then the error is negative if experimental > ...
• 22.3k
3 votes
Accepted

### Significant figures of the product

According to Columbia University Website, Rules for Significant Figures are as follows: All non-zero numbers ARE significant: The number 33.2 has three significant figures because all of the digits ...
• 40.3k
3 votes

### What is a reliable way of writing significant figures in multi-step problems?

For the following, I take 3 to have one significant figure, 67 to have 2 significant figures, and 100 to have one significant figure. If you want to avoid confusion with exact integers (such as a ...
• 40.7k
2 votes

### How to solve a math expression with proper significant digits?

For the record, no scientist actually uses significant figures. They use error bars because you can quantify how big the uncertainty is beyond it is in such and such decimal place. There should be ...
• 17.5k
2 votes

### Ka relating to Dissociation of Weak acid and Water

I think MaxW's answer covers the gist of the question from the calculation side, but its also worth noting something else about your question. $\ce{H^+}$ and $\ce{H3O^+}$ are often used ...
• 11.8k
2 votes
Accepted

### Ka relating to Dissociation of Weak acid and Water

Yes, water autodissociates according to the equation $\ce{2H2O <=> H3O+ + OH-}$. But I should point out that the equilibrium constant is written as though the concentration of water itself is ...
• 22.3k
2 votes

### Significant Figures Calculations

Your answer of $2500$ and the book's answer of $2523$ both have four significant figures. If you want to keep your answer to the same degree of accuracy as the given data with the least number of ...
• 131
2 votes

### How do significant figures work on this computation?

Assuming the precision of the given volume, $V_1 = \pu{400 mL}$, is only to 1 significant figure (i.e. only the hundreds place digit of "4" is precise), then your final answer would be rounded to \$V_2 ...
• 326
2 votes

### A sample must not contain more than 2% contaminants to be pure. Are there instances where 2.12% is ok?

It depends mainly on the accuracy of your measuring instrument in practice and the accuracy required by your work. For example: If you want to make a solution with 2g solute in it, and to measure ...
• 355
2 votes

### A sample must not contain more than 2% contaminants to be pure. Are there instances where 2.12% is ok?

It depends.... The statement "A sample must not contain more than 2% contaminants to be pure" is ambiguous as you have pointed out. To understand exactly what that means requires further ...
• 22.3k

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