Niobium-91 has a half-life of 680 years. After 2,040 years, how much niobium-91 will remain from a 300.0-g sample? 3 g 18.75 g 3
2 answers:
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Explanation:
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Explanation:
Formula for work done is as follows.
W =
where, k = proportionality constant =
d = separation distance = 0.45 nm =
Now, we will put the given values into the above formula and calculate work done as follows.
W =
=
=
Thus, we can conclude that work required to increase the separation of the two ions to an infinite distance is .
Answer:
a. Ca₃(PO₄)₂.
b. 0.010 moles of Ca₃(PO₄)₂ can we expect to be produced
c. 3.1g of Ca₃(PO₄)₂
d. Percent yield = 93.5%
Explanation:
a. Based on the reaction:
3Ca(NO₃)₂(aq) + 2Na₃PO₄(aq) → Ca₃(PO₄)₂(s) + 6NaNO₃(aq)
<em>3 moles of calcium nitrate reacts with 2 moles of sodium phosphate producieng 1 mole of calcium phosphate.</em>
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As you can see, Ca₃(PO₄)₂ is a solid product -(s)-, that means when the reaction occurs the precipitate produced is the solid,
<h3>Ca₃(PO₄)₂</h3><h3 />b. As 3 moles of calcium nitrate produce 1 mole of calcium phosphate and there are 0.030 moles of calcium nitrate
0.030 moles Ca(NO₃)₂ × (1 mol Ca₃(PO₄)₂ / 3 moles Ca(NO₃)₂) =
<h3>0.010 moles of Ca₃(PO₄)₂ can we expect to be produced</h3><h3 />c. As molar mass of Ca₃(PO₄)₂ is 310.18g/mol, the mass of 0.010 moles (The expected mass) is;
0.010 moles Ca₃(PO₄)₂ × (310.18g / mol) =
<h3>3.1g of Ca₃(PO₄)₂</h3><h3 />d. The percent yield is defined as 100 times the ratio between the obtained yield (That is 2.9g of precipitate, Ca₃(PO₄)₂) and the expected yield, 3.1g of Ca₃(PO₄)₂:
Answer:
The mass of an average copper atom is
Explanation:
Given:
The total mass of copper atoms,
Number of atoms,
Now, we are asked to find the mass of 1 copper atom.
We use unitary method to find the mass of 1 copper atom.
Mass of atoms = m
∴ Mass of 1 atom =
Plug in 63.5 for 'm', for 'N' and simply.
Mass of 1 atom =
Therefore, the mass of an average copper atom is