Mass is always conserved in a physical change. Energy may be released or absorbed when a substance changes from one physical state to another. In a chemical change, a chemical reaction yields a completely new substance. A substance's particles are changed during a chemical reaction.
Answer:
The main difference between the heat of formation and heat of reaction is that heat of formation is the amount of energy either absorbed or released during the formation of a compound whereas heat of reaction is the amount of energy either absorbed or released during any chemical reaction.
Answer:
A. 30cm³
Explanation:
Based on the chemical reaction:
CaCO₃ + 2HCl → CaCl₂ + H₂O + CO₂
<em>1 mol of calcium carbonate reacts with 2 moles of HCl to produce 1 mol of CO₂</em>
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To solve this question we must convert the mass of each reactant to moles. With the moles we can find limiting reactant and the moles of CO₂ produced. Using PV = nRT we can find the volume of the gas:
<em>Moles CaCO₃ -Molar mass: 100.09g/mol-</em>
1.00g * (1mol / 100.09g) = 9.991x10⁻³ moles
<em>Moles HCl:</em>
50cm³ = 0.0500dm³ * (0.05 mol / dm³) = 2.5x10⁻³ moles
For a complete reaction of 2.5x10⁻³ moles HCl there are necessaries:
2.5x10⁻³ moles HCl * (1mol CaCO₃ / 2mol HCl) = 1.25x10⁻³ moles CaCO₃. As there are 9.991x10⁻³ moles, HCl is limiting reactant.
The moles produced of CO₂ are:
2.5x10⁻³ moles HCl * (1mol CO₂ / 2mol HCl) = 1.25x10⁻³ moles CO₂
Using PV = nRT
<em>Where P is pressure = 1atm assuming STP</em>
<em>V volume in L</em>
<em>n moles = 1.25x10⁻³ moles CO₂</em>
<em>R gas constant = 0.082atmL/molK</em>
<em>T = 273.15K at STP</em>
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V = nRT / P
1.25x10⁻³ moles * 0.082atmL/molK*273.15K / 1atm = V
0.028L = V
28cm³ = V
As 28cm³ ≈ 30cm³
Right option is:
<h3>A. 30cm³</h3>
Answer:
Bonds basically differs with each other due to sharing of electrons .
Explanation:
There are majorly three kinds of bonds
1. Ionic bonds which forms due to an element donate an electron to another element completely .
2. covalent bonds which forms with the mutual sharing of electrons b/w two atoms .
3. metallic bonds which forms b/w metals & they share electrons due to electron negativity difference b/w two atoms or elements
when an optical telescope located on the ground is used to view the sky the image has to surpass through the earth's atmosphere which is polluted. so the resolution wont be clear. When viewed on a mountain top both optical and infrared telescopes would perform better as the air above the atmosphere is less depth and cleaner.
