Answer:25,06 kJ of energy must be added to a 75 g block of ice.
ΔHfusion(H₂O) = 6,01 kJ/mol.
T(H₂O) = 0°C.
m(H₂O) = 75 g.
n(H₂O) = m(H₂O) ÷ M(H₂O).
n(H₂O) = 75 g ÷ 18 g/mol.
n(H₂O) = 4,17 mol.
Q = ΔHfusion(H₂O) · n(H₂O)
Q = 6,01 kJ/mol · 4,17 mol
Q = 25,06 kJ.
Explanation:
Answer:
They are classified as METALS.
Explanation:
Elements are simple substances that cannot be chemically broken down into smaller substances. Based on different characteristics, they are classified into 3 namely:
- metals
- non metals and
- metalloid( mainly act as semi- conductor).
METALS are the type of elements that loses electrons to form positive ion, that is, they are electropositive elements. They are distinguished by the following characteristics:
- LUSTROUS: they have the ability to reflect light from its surface.
- At room temperature: Metals are solid are room temperature with the exception of Mercury which is liquid at room temperature.
- They react and form Basic Compounds
- Great conductor: most metals are great conductors of heat and electricity because they possess free electrons.
- Melting Point: they have high melting points.
Answer:
The molar mass of Mg(NO₃)₂, 148.3 g/mol.
Explanation:
Step 1: Given data
- Mass of Mg(NO₃)₂ (solute): 42.0 g
- Volume of solution: 259 mL = 0.259 L
Step 2: Calculate the moles of solute
To calculate the moles of solute, we need to know the molar mass of Mg(NO₃)₂, 148.3 g/mol.
42.0 g × 1 mol/148.3 g = 0.283 mol
Step 3: Calculate the molarity of the solution
M = moles of solute / liters of solution
M = 0.283 mol / 0.259 L
M = 1.09 M
Answer:
figure no. A is right answer.......
