Answer:
<em>293.99 g </em>
OR
<em>0.293 Kg</em>
Explanation:
Given data:
Lattice energy of Potassium nitrate (KNO3) = -163.8 kcal/mol
Heat of hydration of KNO3 = -155.5 kcal/mol
Heat to absorb by KNO3 = 101kJ
To find:
Mass of KNO3 to dissolve in water = ?
Solution:
Heat of solution = Hydration energy - Lattice energy
= -155.5 -(-163.8)
= 8.3 kcal/mol
We already know,
1 kcal/mol = 4.184 kJ/mole
Therefore,
= 4.184 kJ/mol x 8.3 kcal/mol
= 34.73 kJ/mol
Now, 34.73 kJ of heat is absorbed when 1 mole of KNO3 is dissolved in water.
For 101 kJ of heat would be
= 101/34.73
= 2.908 moles of KNO3
Molar mass of KNO3 = 101.1 g/mole
Mass of KNO3 = Molar mass x moles
= 101.1 g/mole x 2.908
= 293.99 g
= 0.293 kg
<em><u>293.99 g potassium nitrate has to dissolve in water to absorb 101 kJ of heat. </u></em>
Answer:
Mass of Ag produced = 64.6 g
Note: the question is, how many grams of Ag is produced from 19.0 g of Cu and 125 g of AgNO3
Explanation:
Equation of the reaction:
Cu + 2AgNO3 ---> 2Ag + Cu(NO3)2
From the equation above, 1 mole of Cu reacts with 2 moles of AgNO3 to produce 2 moles of Ag and 1 mole of Cu(NO3)2.
Molar mass of the reactants and products are; Cu = 63.5 g/mol, Ag = 108 g/mol, AgNO3 = 170 g/mol, Cu(NO3)2 = 187.5 g/mol
To determine, the limiting reactant;
63.5 g of Cu reacts with 170 * 2 g of AgNO3,
19 g of Cu will react with (340 * 19)/63.5 g of AgNO3 =101.7 g of AgNO3.
Since there are 125 g of AgNO3 available for reaction, it is in excess and Cu is the limiting reactant.
63.5 g of Cu reacts to produce 108 * 2 g of Ag,
19 g of Cu will react to produce (216 * 19)/63.5 g of Ag = 64.6 g of Ag.
Therefore mass of Ag produced = 64.6g
Yasir wanted to study the relationship between sleep and room color. So he has done all the background study required on the topic and arrived at a hypothesis that people fall asleep more rapidly in a room painted in blue color than in a room painted yellow. Yasir inquired several people which color they like better -yellow or blue- and used their feedback to decide whether his hypothesis was correct. There was no experiment conducted to observe the effect of a room color on sleep and the variables to be tested in the experiment were not properly identified.
Therefore, the correct answer would be,
An experiment that directly tests the hypothesis
Variables to be tested by an experiment
Answer:
.694 moles
Explanation: do given over one so 12.5 over 1 then multiply that by 1 over 18.01528( atomic mass of water) and then you get ans answear that you sig fig but i did that for you
First, find the number of moles for each element. The molar
mass for nitrogen is 14 g/mol and that of hydrogen is 1 g/mol.
1.40 g N / 14 g/mol = 0.1 mol N
0.20 g H / 1 g/mol = 0.2 mol H
Find the mole ratio. Divide both numbers with the much lower
value. In this case, it is 0.1 mol N.
For N: 0.1 ÷ 0.1 = 1
For H: 0.2÷0.1 = 2
Thus, the empirical formula is 
.
