Hi I need help with sig figs with this problem
(0.6216+0.0871)/(0.0740+0.0335)
Actually the problem is this:
Calculate the sodium ion concentration when 74.0 mL of 4.2 M sodium carbonate is added to 33.5 mL of 2.6 M sodium bicarbonate.
My work is:
0.074 g Na2CO3*4.2 mol =0.3108 mol Na2CO3
Na2CO3-->2Na + CO3
2(0.3108) = 0.6216 mol Na+
0.0335L NaHCO3* 2.6mol =0.0871 mol NaHCO3
NaHCO3--> Na + HCO3
1(0.0871 mol NaHCO3)= 0.0871 Na+
M=Total volume of Na/total volume
M=(0.6216 +0.0871)/(0.0740+0.0335)
I got 6.593 but it says I have the sig figs wrong can you please check my work.
Sure, I can help you with that! To determine the number of significant figures in the final answer, you need to follow a few rules. Let's go through the steps together:
Step 1: Add the numbers in the numerator (0.6216 + 0.0871) and the numbers in the denominator (0.0740 + 0.0335).
0.6216 + 0.0871 = 0.7087
0.0740 + 0.0335 = 0.1075
Step 2: Now divide the sum in the numerator by the sum in the denominator.
0.7087 / 0.1075 = 6.5851
Step 3: To identify the correct number of significant figures, you need to find the number with the fewest significant figures among the numbers you divided. In this case, both 0.7087 and 0.1075 have 4 significant figures.
Step 4: The result, 6.5851, should be rounded to match the number with the fewest significant figures. Therefore, the answer should have 4 significant figures.
Now, let's apply the rounding rule. The digit after the last significant figure is 5, which means we round up the preceding digit if it is odd and down if it is even. In this case, the digit before the 5 is 8, an even number. Therefore, we round down.
The final answer, with 4 significant figures, should be 6.585.
So, (0.6216 + 0.0871) / (0.0740 + 0.0335) = 6.585 (rounded to 4 significant figures).