Answer:
Moving Across a Period
Moving from left to right across a period, the atomic radius decreases. The nucleus of the atom gains protons moving from left to right, increasing the positive charge of the nucleus and increasing the attractive force of the nucleus upon the electrons
Answer:
A) Sample B has more calcium carbonate molecules
Explanation:
M = Molar mass of calcium carbonate = 100.0869 g/mol
= Avogadro's number = 
For the 4.12 g sample
Moles of a substance is given by
Number of molecules is given by
For the 19.37 g sample
Number of molecules is given by
So, sample B has more calcium carbonate molecules.
The ratio of the elements of carbon, oxygen, calcium atoms, ions, has to be same in both the samples otherwise the samples cannot be considered as calcium carbonate. Same is applicable for impurities. If there are impurites then the sample cannot be considered as calcium carbonate.
Answer:
Part 1) 85.3 grams NaCl
Part 2) 8.79 x 10²³ formula units NaCl
Explanation:
<u>(Part 1)</u>
To find the mass of NaCl, you need to multiply the given value (1.46 moles) by the molar mass of NaCl. This measurement is the atomic masses of the elements times each of their quantities combined. In this case, there is only one mole of each element in the molecule. Moles should be located in the denominator of the conversion to allow for the cancellation of units. The final answer should have 3 sig figs to reflect the given value.
Molar Mass (NaCl): 22.99 g/mol + 35.45 g/mol
Molar Mass (NaCl): 58.44 g/mol
1.46 moles NaCl 58.44 g
--------------------------- x ---------------- = 85.3 grams NaCl
1 mole
<u>(Part 2)</u>
I do not know which other question the second part is referring to, so I will just use the moles given in the first part. To find the formula units, you need to multiply the given value (1.46 moles NaCl) by Avogadro's Number. This conversion represents the number of formula units found in 1 mole of the sample. The moles should be in the denominator of the conversion to allow for the cancellation of units.
Avogadro's Number:
1 mole = 6.022 x 10²³ formula units
1.46 moles NaCl 6.022 x 10²³ units
------------------------ x ----------------------------- = 8.79 x 10²³ formula units NaCl
1 mole
