To determine the mass of 95% pure \(CaCO_3\) required to neutralise 50 mL of 0.5 M \(HCl\), we need to follow these steps:
1. Understand the reaction: The chemical equation given is \(CaCO_3 + 2HCl \rightarrow CaCl_2 + CO_2 + 2H_2O\). From this, we see that 1 mole of \(CaCO_3\) reacts with 2 moles of \(HCl\).
2. Calculate moles of \(HCl\): Using the formula \(Moles = Molarity \times Volume\ (in\ L)\), we have:
\[0.5 \, \text{M} \times 0.050 \, \text{L} = 0.025 \, \text{moles of } HCl\]
3. Determine moles of \(CaCO_3\) required: From the stoichiometry of the reaction, \(2 \, \text{moles of} \, HCl\) require \(1 \, \text{mole of} \, CaCO_3\). Therefore:
\[0.025 \, \text{moles } HCl \times \frac{1 \, \text{mole } CaCO_3}{2 \, \text{moles } HCl} = 0.0125 \, \text{moles of } CaCO_3\]
4. Calculate mass of pure \(CaCO_3\): Using the molar mass of \(CaCO_3\) (100 g/mol), the mass is:
\[0.0125 \, \text{moles } \times 100 \, \text{g/mol} = 1.25 \, \text{g}\]
5. Adjust for purity: Since the sample is 95% pure, the actual mass required is:
\[1.25 \, \text{g} \div 0.95 = 1.32 \, \text{g}\]
The mass of 95% pure \(CaCO_3\) required is 1.32 g.
Fortification of food with iron is done using $\mathrm{FeSO}_{4} .7 \mathrm{H}_{2} \mathrm{O}$. The mass in grams of the $\mathrm{FeSO}_{4} .7 \mathrm{H}_{2} \mathrm{O}$ required to achieve 12 ppm of iron in 150 kg of wheat is _______ (Nearest integer).} (Given : Molar mass of $\mathrm{Fe}, \mathrm{S}$ and O respectively are 56,32 and $16 \mathrm{~g} \mathrm{~mol}^{-1}$ )
A sphere of radius R is cut from a larger solid sphere of radius 2R as shown in the figure. The ratio of the moment of inertia of the smaller sphere to that of the rest part of the sphere about the Y-axis is : 
AB is a part of an electrical circuit (see figure). The potential difference \(V_A - V_B\), at the instant when current \(i = 2\) A and is increasing at a rate of 1 amp/second is:
Three identical heat conducting rods are connected in series as shown in the figure. The rods on the sides have thermal conductivity 2K while that in the middle has thermal conductivity K. The left end of the combination is maintained at temperature 3T and the right end at T. The rods are thermally insulated from outside. In steady state, temperature at the left junction is \(T_1\) and that at the right junction is \(T_2\). The ratio \(T_1 / T_2\) is 
Stoichiometry is founded on the law of conservation of mass where the total mass of the reactants equals the total mass of the products, leading to the insight that the relations among quantities of reactants and products typically form a ratio of positive integers. This means that if the amounts of the separate reactants are known, then the amount of the product can be calculated. Conversely, if one reactant has a known quantity and the quantity of the products can be empirically determined, then the amount of the other reactants can also be calculated.
Stoichiometry helps us determine how much substance is needed or is present. Things that can be measured are;
The Stoichiometric coefficient of any given component is the number of molecules and/or formula units that participate in the reaction as written.
The mass of one mole of a substance in grams is called molar mass. The molar mass of one mole of a substance is numerically equal to the atomic/molecular formula mass.