Answer:
0.404M
Explanation:
...<em>To make exactly 100.0mL of solution...</em>
Molar concentration is defined as the amount of moles of a solute (In this case, nitrate ion, NO₃⁻) in 1 L of solution.
To solve this question we need to convert the mass of Fe(NO₃)₃ to moles. As 1 mole of Fe(NO₃)₃ contains 3 moles of nitrate ion we can find moles of nitrate ion in 100.0mL of solution, and we can solve the amount of moles per liter:
<em>Moles Fe(NO₃)₃ -Molar mass: 241.86g/mol-:</em>
3.26g * (1mol / 241.86g) =
0.01348 moles Fe(NO₃)₃ * (3 moles of NO₃⁻ / 1mole Fe(NO₃)₃) =
<em>0.0404 moles of NO₃⁻</em>
In 100mL = 0.1L, the molar concentration is:
0.0404 moles of NO₃⁻ / 0.100L =
<h3>0.404M</h3>
Answer: B. High precision
Explanation:
To solve this, we simply equate the change in enthalpy for
the two substances since heat gained by water is equal to heat lost of aluminum.
We know that the heat capacity of aluminum is 0.089 J/g°C and that of water is
4.184 J/g°C. Therefore:
450.2 (95.2 - T) (0.089) = 60 (T – 10) (4.184)
3,814.45456 – 40.0678 T = 251.04 T – 2,510.4
291.1078 T = 6,324.85456
<span>T = 21.7°C</span>
Answer: (3) decomposition and melting
Explanation: Chemical change is one in which chemical composition of substance changes.
Physical change is one in which chemical composition of substance do not change.
Freezing is a process in which a liquid changes into solid phase when allowed to cool. Thus it is a physical change.
Melting : It is process in which a solid changes into liquid phase by providing heat. Thus it is a physical change.
Vaporization : It is process in which liquid changes into gaseous phase by providing heat. Thus it is a physical change.
Decomposition is a chemical reaction in which one substance decomposes to form two or more than two products. Thus the chemical composition change, and hence is a chemical change.
Combustion is a reaction in which a substance combines with oxygen gas to produce carbon dioxide, water and a lot of heat. Thus the chemical composition change, and hence is a chemical change.
