Answer:
A chemical element
Explanation:
A chemical element consists of only one type of atom.
Answer:- solution boiling point = 102.23 degree C (102 degree C with three sig figs).
Solution:- When a non volatile solute is added to a solvent then boiling point increases. Elevation in boiling point is directly proportional to the molality of the solution.
The equation is:
where, 
is the elevation in boiling point, i is the Van't hoff factor, 
is the molal elevation constant and m is the molality.
Value of i is 1 as ethylene glycol is a covalent molecule that does not break to give ions. for water is 
.
We can calculate the molality from the given grams of ethylene glycol and liters of water as molality is moles of solute per kg of solvent.
Molar mass of ethylene glycol is 62 gram per mol and density of water is 1.00 kg per liter.
= 2.50 kg
Let's calculate the moles of ethylene glycol.
= 10.9 mol
molality of the solution = 
= 4.36m
Let's plug in the values in the equation we have on the top for elevation in boiling point.
= 
Boiling point of pure water is 100 degree C. So, the boiling point of the solution = 100 + 2.23 = 102.23 degree C
(If we fix the three sig figs then it could be written as 102 degree C.)
Answer:
C. chromium is a metal that is less reactive than sodium.
Explanation:
Hello.
Given the options:
A. chromium is a nonmetal and therefore a good conductor of heat and electricity
.
B. chromium is a metal that is more reactive than potassium
.
C. chromium is a metal that is less reactive than sodium
.
D. chromium is a noble gas that is not reactive.
In this case, since chromium is in period 4 group VIB we infer it is a transition metal which slightly reacts with acids and poorly reacts with oxygen and other oxidizing substances. Thus, in comparison with both sodium and potassium which are highly reactive even with water as they get on fire, we can say that it is less reactive than both potassium and sodium, therefore, answer is: C. chromium is a metal that is less reactive than sodium.
Best regards.
The balanced chemical reaction is:
Zn + 2AgNO3 = Zn(NO3)2 + 2Ag
To determine the amount of the reactant left, we have to determine which is the limiting and the excess reactant. We do as follows:
5.65 g Zn ( 1 mol / 65.38 g) = 0.09 mol Zn
21.6 g AgNO3 (1 mol / 169.87 g) = 0.13 mol AgNO3
The limiting reactant would be silver nitrate since it is consumed completely in the reaction. The excess reactant would be zinc.
Excess Zinc = 0.09 mol Zn - (0.13 / 2) mol Zn = 0.025 mol Zn left
I’d say A. They are theoretical in the fact that they have not been observed directly, but have been confirmed to exist through experimentation.
