Answer:
B. The number of atoms in a molecular formula is always greater than the number of atoms in an empirical formula.
Explanation:
It is not always true that the number of atoms in a molecular formula is always greater than the number of atoms in an empirical formula.
The chemical formulae of a compound are of two main types;
- The empirical formula is that which expresses the composition of a compound in the simplest whole number ratio.
- The molecular formula shows the actual ratio of the atoms in a compound.
Sometimes the number of atoms in the molecular and empirical formula can be the same.
Also, the number of atoms in the molecular formula is always greater than that of the empirical formula when they are not the same.
Answer:
31.9 °C
Explanation:
The formula for the heat q absorbed by an object is
q = mCΔT where ΔT = (T₂ - T₁)
Data:
q = 12.35 cal
m = 19.75 g
C = 0.125 cal°C⁻¹g⁻¹
T₂ = 37.0 °C
Calculations
(a) Calculate ΔT
q = mCΔT
12.35 cal = 19.25 g × 0.125 cal°C⁻¹g⁻¹ × ΔT
12.35 = 2.406ΔT °C⁻¹
ΔT = 12.35/(2.406 °C⁻¹) = 5.13 °C
(b) Calculate T₂
ΔT = T₂ - T₁
T₁ = T₂ - ΔT = 37.0 °C - 5.13 °C = 31.9 °C
The original temperature was 31.9 °C.
Answer:
0.583 kilojoules
Explanation:
The amount of heat required to pop a single kernel can be calculated using the formula as follows:
Q = m × c × ∆T
Where;
Q = amount of heat (J)
m = mass of water (g)
c = specific heat capacity of water (4.184 J/g°C)
∆T = change in temperature
From the given information, m = 0.905 g, initial temperature (room temperature) = 21°C , final temperature = 175°C, Q = ?
Q = m × c × ∆T
Q = 0.905 × 4.184 × (175°C - 21°C)
Q = 3.786 × 154
Q = 583.044 Joules
In kilojoules i.e. we divide by 1000, the amount of heat is:
= 583.04/1000
= 0.583 kilojoules
What happens when chlorine form an ion is that it gains an electron and has an octet in its outer shell ( answer A)
<u><em> Explanation</em></u>
<u><em> </em></u>Chlorine is is in atomic number 17 in periodic table.
The electron configuration of chlorine is 1S2 2S2 2P6 3S2 3P5 or[Ne]3S2 3p5 or 2.8.7.
chlorine therefore has 7 valence electron therefore it gain 1 electron to form Cl- ( ion)
Cl- has 8 electron in its outer shell ( it obeys octet rule of eight valence in outer shell.
Answer:
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