Potassium is an alkali metal with the chemical symbol K. It has an atomic number of 19, meaning that it has 19 positively charged protons. It also contains 19 electrons, which have a negative charge, and 20 neutrons, which do not hold a charge
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Answer:
A
Explanation:
First, we're given that the atmospheric pressure is 744.8 mmHg. However, this includes the pressure of the Zinc and the pressure of the water; we only want the pressure of the water, so subtract its pressures (23.8 mmHg) from 744.8 mmHg: 744.8 - 23.8 = 721 mmHg.
Now, we can use the ideal gas law: PV = nRT.
- the pressure P is 721 mmHg
- the volume V is 7.80 L
- the moles n of Zinc is what we want to find in order to calculate the mass
- the gas constant R is 62.36 L mmHg / (mol K)
- the temperature T is 25.0°C, or 25.0 + 273 = 298 K
Plug all these in:
PV = nRT
(721 mmHg) * (7.80 L) = n * (62.36) * (298 K)
n ≈ 0.303 mol Zn
We need to convert this to grams, so use the molar mass of Zinc, which is 65.38 g/mol:
Thus, the answer is A.
The mass number of an atom is the sum of its protons and neutrons. the most common isotope of argon is ar-40 (40 ar), with a natural abundance of 99.6 %. the mass number for ar-40 is 40 . It is having 18 protons and 22 neutrons. So its mass number is 40 that is equal to sum of total number of protons and neutrons.
Mass number=total number of protons and neutrons
=18+22
=40
It depends on which particle that you adding or removing
Answer:
1.8 g
Explanation:
Step 1: Write the balanced equation
CH₃CH₃(g) + 3.5 O₂(g) ⇒ 2 CO₂(g) + 3 H₂O(g)
Step 2: Determine the limiting reactant
The theoretical mass ratio of CH₃CH₃ to O₂ is 30.06:112.0 = 0.2684:1.
The experimental mass ratio of CH₃CH₃ to O₂ is 0.60:3.52 = 0.17:1.
Thus, the limiting reactant is CH₃CH₃
Step 3: Calculate the mass of CO₂ produced
The theoretical mass ratio of CH₃CH₃ to O₂ is 30.06:88.02.
0.60 g CH₃CH₃ × 88.02 g CO₂/30.06 g CH₃CH₃ = 1.8 g