Answer:
The number of protons is equal to the mass number of the element. Since an element always has a different number of protons, the mass can indicate how many neutrons are in an isotope. Atoms of the same element can have a different number of neutrons. There are three naturally-occurring isotopes of carbon.
Explanation:
Answer:
A. 0.143 M
B. 0.0523 M
Explanation:
A.
Let's consider the neutralization reaction between potassium hydroxide and potassium hydrogen phthalate (KHP).
KOH + KHC₈H₄O₄ → H₂O + K₂C₈H₄O₄
The molar mass of KHP is 204.22 g/mol. The moles corresponding to 1.08 g are:
1.08 g × (1 mol/204.22 g) = 5.28 × 10⁻³ mol
The molar ratio of KOH to KHC₈H₄O₄ is 1:1. The reacting moles of KOH are 5.28 × 10⁻³ moles.
5.28 × 10⁻³ moles of KOH occupy a volume of 36.8 mL. The molarity of the KOH solution is:
M = 5.28 × 10⁻³ mol / 0.0368 L = 0.143 M
B.
Let's consider the neutralization of potassium hydroxide and perchloric acid.
KOH + HClO₄ → KClO₄ + H₂O
When the molar ratio of acid (A) to base (B) is 1:1, we can use the following expression.
Answer:
The specific heat of iron is 0.45 J/g.°C
Explanation:
The amount of heat absorbed by the metal is given by:
heat = m x Sh x ΔT
From the data, we have:
heat = 180.8 J
mass = m = 22.44 g
ΔT = Final temperature - Initial temperature = 39.0°C - 21.1 °C = 17.9°C
Thus, we calculate the specific heat of iron (Sh) as follows:
Sh = heat/(m x ΔT) = (180.8 J)/(22.44 g x 17.9°C) = 0.45 J/g.°C
Answer:
315.51g/mol
Explanation:
137(33 + (16.00 + 1.01) 2 + 8 [1.01 (2) + 16.00] = 315.51g/mol
Answer:
A.The two ends are like poles
Explanation:
Magnets are composed of a north pole and a south pole. If two like poles of a magnetic are placed near each other, the two ends seem to push apart.
The reason for this is that, when like poles of two magnets are made to face each other, the lines of forces are in opposite directions, hence the magnets repel.
If unlike poles of two bar magnets are made to face each other, the magnetic lines of force are now in the same direction therefore the unlike poles attract each other.
