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The recommended daily dose of calcium is 1200 mg. Calcium supplements often use calcium carbonate, $CaCO_3$, as the source of calcium. What mass of $CaCO_3$ should be used in a tablet so that one tablet provides the recommended daily dose of calcium?
$"Moles of calcium"$ $=$ $(1200xx10^-3*g)/(40.08*g*mol^-1)$ $=$ $0.04008*mol$. And thus we need $0.04008*mol$ $"calcium carbonate"$, i.e. a mass of $0.04008*molxx100.09*g*mol^-1$ $=$ $??g$.
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What is the electron configuration for an excited atom of phosphorous, ready to emit a photon of energy and return to ground state? (configuration has to follow all rules except be in lowest energy)
Phosphorus has $15$. As such its electronic configuration in ground state is $1s^2 2s^2 2p^6 3s^2 3p^3$ The following electronic configurations could be excited states $1s^2 2s^2...
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An electron is excited from the n=1 ground state to the n=3 state in a hydrogen atom. Does it take more energy to ionize (completely remove) the electron from n=3 than from the ground state?
.........does it take you more energy to climb from the bottom of the stairs, than from 3 steps up the flight of stairs? Quite clearly it does. When...
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A sodium atom has an electron configuration of $1s^2 2s^2 2p^6 3s^1$. If the sodium atom becomes ionized, its new electron configuration will be the same as which element?
If the sodium is ionised, the outer $3s^1$ electron is lost, so the configuration becomes $1s^2 2s^2 2p^6$, which is the same as neon, $Ne$.
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I need some help understanding how some ions have the same electronic arrangement as noble gasses? Like why does a Li+ ion has the same electron structure as helium or a Mg2+ ion has the same electron structure
as a Na+ ion and an O2- ion?
A completely filled outer electron shell is stable because it can not gain any more electrons, it is full. Being completely full it has no desire to lose electrons thereby...
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Decomposing calcium carbonate yields calcium oxide and dioxide. What information is needed to calculate the mass of calcium oxide that can produced from 4.7 kg of calcium carbonate?
The balanced chemical equation The molar mass of $"CaCO"_3$ The molar ratio of $"CaO"$ to $"CaCO"_3$ The molar mass of $"CaO"$ Your strategy has four steps:...
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Calcium carbonate decomposes to form calcium oxide and carbon dioxide gas. If 44.5 grams of calcium oxide is produced, how many grams of calcium carbonate had to decomposez?
We need a stoichiometric reaction that represents the decomposition of calcium carbonate: $CaCO_3(s) + Delta rarr CaO(s) + CO_2(g)uarr$ And thus calcium oxide and calcium carbonate are present in equimolar...
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A $2.03*g$ mass of calcium salts contains $1.33*g$ calcium carbonate. What is the $%$ calcium carbonate; and what is the percentage by mass of of calcium in calcium carbonate?
So we have the $"%calcium carbonate, "m/m$. We are not finished yet, because we have to address the percentage by mass of calcium metal in calcium carbonate: $%Ca=(40.08*g*mol^-1)/(100.09*g*mol^-1)=40%$ with respect...
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Calcium oxide and carbon dioxide are produced from the decomposition of calcium carbonate. How many moles of calcium carbonate are needed to produce 15.0 grams of the calcium oxide?
We interrogate the stoichiometric equation...... $CaCO_3(s) + Delta rarr CaO(s) + CO_2(g) uarr$ We require a molar quantity of $(15.0*g)/(56.08*g*mol^-1)=0.268*mol,$ with respect to $"calcium oxide"$. And clearly, we need a...
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Suppose 1.2 grams of calcium hydroxide are dissolved in 1.75 L of an aqueous solution. How do you determine the following: hydroxide ion concentration, hydronium ion concentration, calcium ion concentration, pH and poH?
And generally, we report $"concentration"$ with units of $mol*L^-1$. And so $[Ca(OH)_2]=((1.2*g)/(74.09*g*mol^-1))/(1.75*L)=9.26xx10^-3*mol*L^-1$. Clearly, $[HO^-]=2xx9.26xx10^-3*mol*L^-1$. Agreed? Because $[Ca(OH)_2]$ speciates in solution to give $Ca^(2+)$, and 2 equiv of hydroxide ion....
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