Answer:d
Explanation:test
atm. What is the partial pressure (atm) of argon?
(2) The nucleus is positive and the electron cloud is negative.
(3) The nucleus is negative and the electron cloud is positive.
(4) The nucleus is negative and the electron cloud is negative.
Atoms are made of nucleus and electrons. Nucleus have a positive charge due to the presence of protons and electrons are negative in charge . Thus option 2 is correct.
Atoms are the basic unit every substance. Atoms combines to form molecules and compounds. An atom is made of nucleus and surrounding electrons which are revolving through a circular path of fixed energy.
Nucleus is the core of the atom and the 90% of the weight of atom is centered in the nucleus and it contains positively charged protons and neutral particles neutrons.
The nuclear model of atom was first proposed by Rutherford. He found the positive cloud of the atom and and named as nucleus. He discovered the positively charged particles protons.
The net charge of an atom is zero because all the positive charges are neutralised by equal number of negatively charged particles electrons.
Therefore, the nucleus is positive and the electron cloud is negative and option 2 is correct.
To find more about atomic nucleus, refer the link below:
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Answer:
pH=8.32
Explanation:
The relevant equilibrium for this problem is
F⁻ + H₂O ↔ HF + OH⁻
With a constant Kb of
Kb=
Kb=
To calculate the value of Kb we use the formula Kw=Ka*Kb, where Kw is the ionization constant of water, 1 * 10⁻¹⁴.
1 * 10⁻¹⁴ = 7.2*10⁻⁴ * Kb
Kb = 1.4 * 10⁻¹¹
So now we have
1.4 * 10⁻¹¹=
We make the assumption that x<<<0.30 M, so we can rewrite the equation of Kb as:
1.4 * 10⁻¹¹=
So [OH⁻]=2.05*10⁻⁶
6.21 × 10²² Carbon Atoms
Data Given:
Mass of Butane (C₄H₁₀) = 1.50 g
M.Mass of Butane = 58.1 g.mol⁻¹
Step 1: Calculate Moles of Butane as,
Moles = Mass ÷ M.Mass
Putting values,
Moles = 1.50 g ÷ 58.1 g.mol⁻¹
Moles = 0.0258 mol
Step 2: Calculate number of Butane Molecules;
As 1 mole of any substance contains 6.022 × 10²³ particles (Avogadro's Number) then the relation for Moles and Number of Butane Molecules can be written as,
Moles = Number of C₄H₁₀ Molecules ÷ 6.022 × 10²³ Molecules.mol⁻¹
Solving for Number of Butane molecules,
Number of C₄H₁₀ Molecules = Moles × 6.022 × 10²³ Molecules.mol⁻¹
Putting value of moles,
Number of C₄H₁₀ Molecules = 0.0258 mol × 6.022 × 10²³ Molecules.mol⁻¹
Number of C₄H₁₀ Molecules = 1.55 × 10²² C₄H₁₀ Molecules
Step 3: Calculate Number of Carbon Atoms:
As,
1 Molecule of C₄H₁₀ contains = 4 Atoms of Carbon
So,
1.55 × 10²² C₄H₁₀ Molecules will contain = X Atoms of Carbon
Solving for X,
X = (1.55 × 10²² C₄H₁₀ Molecules × 4 Atoms of Carbon) ÷ 1 Molecule of C₄H₁₀
X = 6.21 × 10²² Atoms of Carbon
of carbon is present in 1.50 g of butane.
Further Explanation:
Avogadro’s number indicates how many atoms or molecules a mole can have in it. In other words, it provides information about the number of units that are present in one mole of the substance. It is numerically equal to . These units can be atoms or molecules.
The formula to calculate the moles of is as follows:
…… (1)
Substitute 1.50 g for the given mass and 58.1 g/mol for the molar mass of in equation (1).
Since one mole of has of . Therefore the formula to calculate the molecules of butane is as follows:
…… (2)
Substitute 0.0258 mol for the moles of and for Avogadro’s number in equation (2).
The chemical formula of butane is . This indicates one molecule of butane has four atoms of carbon. Therefore the number of carbon atoms can be calculated as follows:
Learn more:
Answer details:
Grade: Senior School
Chapter: Mole concept
Subject: Chemistry
Keywords: 1.50 g, 58.1 g/mol, butane, C4H10, Avogadro’s number, C atoms, molecules, moles, one mole, chemical formula, carbon atoms, molar mass of C4H10, given mass of C4H10.