Answer:
3
Explanation:
A cyclic event is one that happens repeatedly.
The appearance of Hailey's Comet is a cyclic event because it has happened in various occasions in the past on a regular schedule as predicted. We have every reason to believe that the appearance of Hailey's Comet every 75 years will continue to be happen until the comet ceases to exist.
The reaction that is a double displacement reaction is the final one. Between Pb(NO3)2 and HCl.
Answer:
C₂H₇F₂P
Explanation:
Given parameters:
Composition by mass:
C = 24%
H = 7%
F = 38%
P = 31%
Unknown:
Empirical formula of compound;
Solution :
The empirical formula is the simplest formula of a compound. To solve for this, follow the process below;
C H F P
% composition
by mass 24 7 38 31
Molar mass 12 1 19 31
Number of
moles 24/12 7/1 38/19 31/31
2 7 2 1
Dividing
by the
smallest 2/1 7/1 2/1 1/1
2 7 2 1
Empirical formula C₂H₇F₂P
Answer:
D
Explanation:
The sample must contain impurity that is lower in atomic mass to sodium and since potassium has higher atomic mass to sodium, the answer is the sample contains NaCl and LiCl. We are sure already that the sample is not pure which rules out option a and option b contains sodium iodide which cannot contribute to the increase in chlorine
In nature, boron is monoatomic. Therefore, its formula is B.
On the other hand, fluorine is diatomic. Therefore, its formula is F2
Now, the basic unbalanced equation is:
B + F2 .........> BF3
Now, we need to balance this equation. As you can see, we have two fluorine moles entering the reaction and 3 formed in the products.
Balancing the equation, we will reach the following balanced reaction:
2B + 3F2 .......> 2BF3
