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Kruka [31]
3 years ago
13

Match the element with its number of valence electrons. Column A 1. Boron : Boron 2. Carbon : Carbon 3. Fluorine : Fluorine 4. S

odium : Sodium Column B a. 4 b. 1 c. 3 d. 7
Chemistry
1 answer:
Paha777 [63]3 years ago
6 0
Boron 3
Carbon 4
Fluorine 7
Sodium 1
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If 1.80 moles of NaCl was dissolved in enough water to make 3.60 L of solution, what is the Molarity?
sweet-ann [11.9K]

Answer:

0.5M

Explanation:

The equation for molarity is:

  • M = \frac{mol}{liters} ; where the "M" stands for molarity, the "mol" stands for moles of solute and the "liters" means the volume in liters of solution.

We are given that there are:

  • 1.80 moles of NaCl (the moles of solute)
  • 3.60 Liters of solution (the volume in liters of solution)

Now we just plug those numbers into the formula and get our answer:

  • M= \frac{1.80mol}{3.60L}= 0.5M

After doing the math and dividing the moles of solute by the liters of solution, we get that the molarity of the solution is 0.5M.

8 0
3 years ago
Complete the acid–base equation for the dissolution of the following compound into liquid HF solvent. The relevant pKa values ar
LenKa [72]

Answer:

The balanced chemical equation: NH₃ + 2 HF → NH₄⁺ + HF₂⁻

Explanation:

According to the Brønsted–Lowry acid–base theory, the acid- base reaction is a type of chemical reaction between the acid and base to give a conjugate acid and a conjugate base.

In this reaction, a Brønsted–Lowry acid loses a proton to form a conjugate base. Whereas, a Brønsted–Lowry base accepts a proton to form a conjugate acid.

Acid + Base ⇌ Conjugate Base + Conjugate Acid

The acid dissociation constant (Kₐ) <em>signifies the acidic strength of a chemical species.</em>

∵ pKₐ = - log Kₐ

Thus for a strong acid, Kₐ value is large and pKₐ value is small.

pKₐ (HF) = 3.2 → strong acid

pKₐ (NH₃) = 38 → weak acid

<u>The chemical reaction involved in the dissolution process:</u>

NH₃ + 2 HF → NH₄⁺ + HF₂⁻

In this acid-base reaction, the acid HF reacts with NH₃ base to give the conjugate base HF₂⁻ and conjugate acid NH₄⁺.

<u>HF (acid) donates a proton to form the conjugate base, HF₂⁻ ion. NH₃ (base) accepts a proton to form the conjugate acid. </u>

7 0
3 years ago
The following reactions can be used to prepare samples of metals. Determine the enthalpy change under standard state conditions
mamaluj [8]

Answer:

a) 62.1 kJ/mol

b) 2.82 kJ/mol

c) 270.91 kJ/mol

d) -851.5 kJ/mol

Explanation:

The enthalpy change for a reaction in standard conditions (ΔH°rxn) can be calculated by:

ΔH°rxn = ∑n*ΔH°f, products - ∑n*ΔH°f, reagents

Where n is the number of moles in the stoichiometry reaction, and ΔH°f is the enthalpy of formation at standard conditions. ΔH°f = 0 for substances formed by only a single element. The values can be found in thermodynamics tables.

a) 2Ag₂O(s) → 4Ag(s) + O₂(g)

ΔH°f, Ag₂O(s) = -31.05 kJ/mol

ΔH°rxn = 0 - (2*(-31.05)) = 62.1 kJ/mol

b) SnO(s) + CO(g) → Sn(s) + CO₂(g)

ΔH°f,SnO(s) = -285.8 kJ/mol

ΔH°f,CO(g) = -110.53 kJ/mol

ΔH°f,CO₂(g) = -393.51 kJ/mol

ΔH°rxn = [-393.51] - [-110.53 - 285.8] = 2.82 kJ/mol

c) Cr₂O₃(s) + 3H₂(g) → 2Cr(s) + 3H₂O(l)

ΔH°f,Cr₂O₃(s) = -1128.4 kJ/mol

ΔH°f,H₂O(l) = -285.83 kJ/mol

ΔH°rxn = [3*(-285.83)] - [( -1128.4)] = 270.91 kJ/mol

d) 2Al(s) + Fe₂O₃(s) → Al₂O₃(s) + 2Fe(s)

ΔH°f,Fe₂O₃(s) = -824.2 kJ/mol

ΔH°f,Al₂O₃(s) = -1675.7 kJ/mol

ΔH°rxn = [-1675.7] - [-824.2] = -851.5 kJ/mol

3 0
3 years ago
HELP ME PLEASE (brainliest)
Aloiza [94]

Answer: i would say D or the last one.

Explanation: According to the law of conservation of mass, the mass of the products in a chemical reaction must equal the mass of the reactants. The law of conservation of mass is useful for a number of calculations and can be used to solve for unknown masses, such the amount of gas consumed or produced during a reaction.

Hope this helps :) Can u plz mark me branliest

7 0
2 years ago
Material Conductor or Insulator foam insulator aluminum conductor wool insulator ? conductor Which material BEST completes the c
kirill115 [55]
Sorry but i can not decide i think it is B or C

5 0
3 years ago
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