Answer:
[HF]₀ = 0.125M
Explanation:
NaOH + HF => NaF + H₂O
Adding 20ml of 0.200M NaOH into 25ml of HF solution neutralizes 0.004 mole of HF leaving 0.004 mole NaF in 0.045L with 0.001M H⁺ at pH = 3. This is 0.089M NaF and 0.001M HF remaining.
=> 45ml of solution with pH = 3 and contains 0.089M NaF from titration becomes a common ion problem.
HF ⇄ H⁺ + F⁻
C(eq) [HF] 10⁻³M 0.089M (<= soln after adding 20ml 0.200M NaOH)
Ka = [H⁺][F⁻]/[HF]₀ => [HF]₀ = [H⁺][F⁻]/Ka
[HF]₀ = (0.001)(0.089)/(7.1 x 10⁻⁴) M = 0.125M
Answer:
2) 0.4 mol
Explanation:
Step 1: Given data
- Volume of the solution (V): 500 mL
- Molar concentration of the solution (M): 0.8 M = 0.8 mol/L
Step 2: Convert "V" to L
We will use the conversion factor 1 L = 1000 mL.
500 mL × 1 L/1000 mL = 0.500 L
Step 3: Calculate the moles of KBr (solute)
The molarity is the quotient between the moles of solute (n) and the liters of solution.
M = n/V
n = M × V
n = 0.8 mol/L × 0.500 L = 0.4 mol
The balanced chemical reaction is:
<span>2C4H10(g)+13O2(g)->10H2O(g)+8CO2(g)
</span>
<span>Calculate the mass of water produced when 1.77 grams of butane reacts with excessive oxygen?
</span>1.77 g C4H10 (1 mol C4H10/58.14 g C4H10) (10 mol H2O / 2 mol C4H10) ( 1.01 g H2O / 1 mol H2O ) = <span>0.15 g H2O
</span><span>Calculate the mass of butane needed to produce 71.6 of carbon dioxide.
</span>71.6 g CO2 (1 mol CO2/ 44.01 g CO2) ( 2 mol C4H10 / 8 mol CO2 ) (58.14 g C4H10 / 1 mol C4H10 ) = 23.65 g C4H10
Answer:
According to the definitions given, atomic mass which is also called atomic weight is the measured total mass of an element's atom. Whereas, atomic number is nothing but the total number of neutrons and protons in the nucleus of an atom....
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Answer:
Atoms bind because, being united, they acquire a more stable situation than when they were separated and this allows them to exist in nature. This situation of greater stability usually occurs when the number of electrons that possess the atoms in their last level is equal to eight, structure that coincides with that of the noble gases.
Quemical bonding refers to the attraction forces that keep bonded the atoms in compounds, and there are two main types of chemical bonding: ionic and covalent bonding.
Explanation:
1)<u> Ionic bond:</u> results of the electrostatic interaction between ions, that results in the net transfer of one or more electrons from one atoms or group of atoms to other atom.
<em><u>Example of ionic bond:</u></em>
Sodium Chloride Na-Cl +, Sodium ion has a positive charge and chlorine ion has a negative charge, so chlorine seats an electron to sodium creating a ionic bond.
2)<u> Covalent bond:</u> In this type of chemical bond two atoms shares one or more pairs of electrons.
<em><u>Example of covalent bond</u></em>
Carbon monoxide is an example of a compound that has covalent bond, one carbon atom and one oxygen atom, linked by a triple bond that consists of two covalent bonds as well as one dative covalent bond.
