Explanation
To find the mass from the given number of moles of the compound or molecule or atom.Use this formula
mass = moles x MM
where MM is the molar mass of the compound .To find the molar mass of CaCl2, consider the number of atoms of each element in the formula then multiply the number of elements with their atomic masses then finally add all the molecular weight.
CaCl2 has 1 Ca atom , 2 Cl atoms.
Ca = 1 x 40.07 = 40.07
Cl = 2 x 35.45 = 70.9
40.07 + 70.9 = 110.97 g / mol
mass = 0.89 x 110.97 = 98.76 g
Answer
98.76 g
Answer Choice: C
Explanation: Mendeleev is best known for publishing the first periodic table of elements in 1869, revolutionizing the world's understanding of physics and chemistry; and, really almost every aspect of science.
Answer:
Option (D) freezing point depression
Explanation:
Calcium chloride is added to the roadways after a snowstorm because it reduces the freezing point of the ice. Further more, it has been observed that the calcium chloride also produces enough heat which enhances the melting of the ice as it produces an exothermic reaction.
1) in periodic acid (HIO₄), iodine has oxidation number +7, hydrogen has oxidation number +1, oxygen has -2, compound has neutral charge:
+1 + x + 4 · (-2) = 0.
x = +7.
2) in molecule of iodine (I₂), iodine has oxidation number 0, because iodine is nonpolar molecule.
3) in sodium iodide (NaI), iodine has oxidation number -1, sodium has oxidation number +1:
+1 + x = 0.
x = -1.
4) in iodic acid (HIO₃), iodine has oxidation number +5, hydrogen has oxidation number +1, oxygen has -2, compound has neutral charge:
+1 + x + 3 · (-2) = 0.
x = +5.
Answer:
2621.75 j heat is required to increase the temperature 25.5°C to 46°C.
Explanation:
Given data:
Mass of sample = 142.1 g
Initial temperature = 25.5°C
Final temperature = 46°C
Specific heat capacity of Al = 0.90 J/g.°C
Solution:
Formula:
Q = m.c. ΔT
Q = amount of heat absorbed or released
m = mass of given substance
c = specific heat capacity of substance
ΔT = change in temperature
ΔT = 46°C - 25.5°C
ΔT = 20.5°C
Q = 142.1 × 0.90 J/g.°C × 20.5°C
Q = 2621.75 j
Thus, 2621.75 j heat is required to increase the temperature 25.5°C to 46°C.
