Hello!
Find the empirical formula of a compound which contains 54.93% potassium, 38.73% boron and 6.34% hydrogen.
A. KBH
B. KB2H4
C. KB3H9
D. K2B5H9
Potassium (K) ≈ 39 a.m.u (g/mol)
Boron (B) ≈ 11 a.m.u (g/mol)
Hydrogen (H) ≈ 1 a.m.u (g/mol)
K: 54.93 % = 54.93 g
B: 38.73 % = 38.73 g
H: 6.34 % = 6.34 g
convert number of atomic radio into whole number
2 * (1 : 2.5 : 4.5)
= 2 : 5 : 9 ← whole number of atomic radio
K = 2
B = 5
H = 9
Answer:
D. K2B5H9
________________________
(1) CaCO3(s) --> CaO(s) + CO2(g)
(2) 2 Mg(s) + O2(g) --> 2 MgO(s)
(3) H2O(g) --> H2O(l)
(4) CO2(g) --> CO2(s)
Answer:
Was this correct? I am pretty sure it is since you are going from a solid to a gas in the first reaction.
Explanation:
(1) CaCO3(s) --> CaO(s) + CO2(g) --- solid to solid & gas ** most entropy here
(2) 2 Mg(s) + O2(g) --> 2 MgO(s) solid & gas to a solid
(3) H2O(g) --> H2O(l) gas to a liquid
(4) CO2(g) --> CO2(s) gas to a solid
As temperature rises and a substance transforms from a solid to a liquid to a gas, entropy increases. Because they have the most flexibility to move, gases have the highest entropy values. Here the first reaction has high entropy. The correct option is 1.
The level of unpredictability in a system is known as entropy. The degree of randomness is highest when comparing the three forms of matter solid, liquid, and gas because the gas particles move freely.
(1) CaCO3(s) --> CaO(s) + CO2(g) --- solid to solid & gas - most entropy here
(2) 2 Mg(s) + O2(g) --> 2 MgO(s) solid & gas to a solid
(3) H2O(g) --> H2O(l) gas to a liquid
(4) CO2(g) --> CO2(s) gas to a solid
Thus the correct option is 1.
To know more about entropy, visit;
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collect more data to support their hypothesis
O A physical change does not change the chemical formula of the substance
O A physical change has similar characteristics as a chemical change.
A physical change is a change in how the substances react with other substances.
The correct answer is physical change does not change the chemical formula of the substance.
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Answer:
B. a physical change does not change the chemical formula of the substance
Explanation:
Physical change does not change the substance or identity of an object
Answer:
3) Each sample has the same number of molecules
Explanation:
1 mol are 6,022x10²³ particles. Moles of a chemical substance represent the number of molecules that this chemical has.
Thus, one mol of oxygen are 6,022x10²³ molecules of oxygen and one mol of nitrogen are 6,022x10²³ molecules of nitrogen.
Right answer is:
3) Each sample has the same number of molecules.
I hope it helps!
B. There are two carbon atoms and a double carbon bond.
C. There are three carbon atoms and a double carbon bond that starts on the second carbon atom.
D. There are four carbon atoms and a double carbon bond that starts on the second carbon atom.
Gradpoint answer: a four-carbon hydrocarbon with a double bond between the second and third carbon atoms