now that i do and I also believe adopt don't shop and also no puppy mill.
Option B: 4.3
There are following rules for rounding off numbers:
1. If the rounding digit has digit less than 5 (1,2,3 and 4) to its right, all the digits on right side of the rounding digit will drop out.
2. If the rounding digit has digit equal and greater than 5 (5,6,7,8 and 9) to its right, one is added to the rounding digit.
Jeff has to weigh 4.312 g sample of NaCl. To round off the underline number 4.<u>3</u>12, check for the digit right to it. It has 1, which is less than 5 thus according to the Rule 1, all the digits on right side of the rounding digit will drop out and the number gets rounded off to 4.3.
Therefore, 4.3 is most accurate measurement by Jeff.
Explanation:
It is known that stronger is the bonding between the atoms of a molecule more difficulty it will face to form vapors. Hence, more heat needs to be provided to the molecule. As a result, it will have high boiling point.
So, in heptanol there is hydrogen bonding. Hence, there is strong bonding so, boiling point of heptanol will be high.
On the other hand, heptane has long carbon chain as compared to pentane. Therefore, heptane will occupy more surface area and thus, more heating will be provided to it. Hence, boiling point of heptane will be greater than the boiling point of pentane.
Thus, we can conclude that rank of given compounds according to start of their boiling point is as follows.
pentane < heptane < heptanol
<span>Answer: 1.06 moles of molecules = 6.38x10²³ molecules
</span><span />
<span>Explanation:
</span><span />
<span>1) Balanced chemical equation:
</span><span />
<span>2Na + 2H₂O -> 2NaOH + H₂
</span><span />
<span>2) Mole ratios:
</span><span />
<span>2 mol Na : 2 mol H₂O : 2 mol NaOH : 1 mol H₂
</span><span />
<span>3) Convert 48.7 g of sodium to moles:
</span><span />
<span>number of moles = mass in grams / molar mass
</span><span />
<span>molar mass of Na = atomic mass = 23.0 g/mol
</span><span>number of moles = 48.7g / 23.0 g/mol = 2.12 moles of Na</span>
<span /><span>
4) Proportion:
</span><span />
<span>2moles Na/1mol H₂ = 2.12 moles Na / x
</span><span />
<span>x = 2.12 moles Na * 1 mol H₂ / 2 moles Na = 1.06 moles H₂.
</span><span />
<span>5) If you want to convert that to number of molecules you have to multiply by Avogadro's number: 6.022 x 10^²³
</span><span />
<span>1.06 mol x 6.022x10^²³ molecules/mol = 6.38x10²³ molecules</span>
Answer:
Major Elements
The six most common elements inliving things are carbon, hydrogen, oxygen, nitrogen, phosphorus, and sulfur. Atoms of these elementscombine and form thousands of large molecules. These large molecules make up the structures of cells and carry out many processes essential to life.
