Which mixture is classified as a solution?

If you have 0.50 mol of ca, how many atoms are present?

Evgen [1.6K]

Answer is: there are 3.011·10²³ atoms of calcium.

n(Ca) = 0.50 mol; amount of substance(calcium).
Na = 6.022·10²³ 1/mol; Avogadro's constant or number.
N(Ca) = n(Ca) · Na.
N(Ca) = 0.50 mol · 6.022·10²³ 1/mol.
N(Ca) = 3.011·10²³; number of calcium atoms.
The mole is an SI unit which measures the number of particles in substance. One mole is equal to 6.022·10²³ atoms.

6 0

3 years ago

Semimetals is a term which refers to

SCORPION-xisa [38]

I guess you could call them that. In chemistry, we call them Metalloids though.

5 0

2 years ago

Researchers tested a meteorite for organic molecules containing 13C and 15N, which are carbon and nitrogen atoms with one extra

Hoochie [10]

Answer:

The correct option is 2.No, because only electrons are involved in bonding.

Explanation:

The type of bond formed by carbon and nitrogen (carbon-nitrogen bond) is covalent bond

Also known as molecular bond, a covalent bond involves the sharing of pairs of electrons (known as bonding pairs or shared pairs) between the carbon and nitrogen atoms forming stable, balanced forces in attraction and repulsion as they share common electrons in their compounds.

This electron sharing covalent bond is what enables the formation of the several compounds between carbon and nitrogen for example, in an amine, nitrogen which has five electrons, has two remaining electrons that forms a lone pair whereby it can combine further with other elements.

Hence the factor that influences the bonds to make the numerous organic molecules is the available electrons which constitutes the shared electron pairs in covalent bonds while the neutrons which function is to keep the repulsive forces of positively charged protons from ripping the nucleus apart.

3 0

3 years ago

I just need answers please!!

otez555 [7]

Answer:

#1 is an organism

#2 is cell

#4 - Digestive System gets nutrients (good) from food and hands it over to the blood and Circulatory System then carries those nutrients where they need to go

4 0

3 years ago

Read 2 more answers

Glycolic acid, which is a monoprotic acid and a constituent in sugar cane, has a pKa of 3.9. A 25.0 mL solution of glycolic acid

Phoenix [80]

Answer:

pH = 8.0

Explanation:

First, we have to calculate the moles of NaOH.

$35.8 \times 10^{-3}L.\frac{0.020mol}{L} =7.2\times 10^{-4}mol$

Let's consider the balanced equation.

C₂H₄O₃ + NaOH ⇒ C₂H₃O₃Na + H₂O

The molar ratio C₂H₄O₃: NaOH: C₂H₃O₃Na is 1: 1: 1. So, when 7.2 × 10⁻⁴ moles of NaOH react completely with 7.2 × 10⁻⁴ moles of C₂H₄O₃ they form 7.2 × 10⁻⁴ moles of C₂H₃O₃Na.

The concentration of C₂H₃O₃Na is:

$\frac{7.2\times 10^{-4}mol}{60.8 \times 10^{-3}L} =0.012M$

C₂H₃O₃Na dissociates according to the following equation:

C₂H₃O₃Na(aq) ⇒ C₂H₃O₃⁻(aq) + Na⁺(aq)

C₂H₃O₃⁻ comes from a weak acid so it undergoes basic hydrolisis.

C₂H₃O₃⁻ + H₂O ⇄ C₂H₄O₃ + OH⁻

If we know that pKa for C₂H₄O₃ is 3.9, we can calculate pKb for C₂H₃O₃⁻ using the following expression:

pKa + pKb = 14

pKb = 14 -3.9 = 10.1

10.1 = -log Kb

Kb = 7.9 × 10⁻¹¹

We can calculate [OH⁻] using the following expression:

[OH⁻] = √(Kb.Cb) where Cb is the initial concentration of the base

[OH⁻] = √(7.9 × 10⁻¹¹ × 0.012M) = 9.7 × 10⁻⁷ M

Now, we can calculate pOH and pH.

pOH = -log [OH⁻] = -log (9.7 × 10⁻⁷) = 6.0

pH + pOH = 14

pH = 14 - pOH = 14 - 6.0 = 8.0

7 0

2 years ago