Answer:
Explanation:
The dilution formula is:
Where M₁ and M₂ are the molar concentrations and V₁ and V₂ are the volumes of the concentrated and the diluted solutions.
Substitute:
Clear M₂ and compute:
Answer:
Explanation:acid etching
etching
the cutting of a hard surface such as metal or glass by a corrosive chemical, usually an acid, in order to create a design.
etching - etching of dental enamel with an acid in order to roughen the surface, increase retention of resin sealant, and promote mechanical retention.
acid etching
microscopic roughening of dental enamel with an acid (usually phosphoric acid) to remove the smear layer and open enamel tubules, increase retention of resin sealant, and promote mechanical retention.
acid etching Dentistry
The application of a weak acid—e.g., 30% phosphoric acid—to the surface of enamel to roughen the surface of a tooth before bonding a resin or veneer; acid etching increases mechanical retention, cleans the enamel and improves the wetting of resins. See Cosmetic dentistry.
Answer:
through Decantation
Explanation:
Decantation: Decantation is pouring out of upper clear layer of liquid into another container to separate two immiscible liquids or to separate different substances in a suspension mixture.
Therefore, we could use decantation once the sand particles settle down by gently pouring the water into another container. Once the water is transfered, we'll be left with sand in the bottom of the first container.
Hope that helps...
Answer:
59.077 kJ/mol.
Explanation:
- From Arrhenius law: <em>K = Ae(-Ea/RT)</em>
where, K is the rate constant of the reaction.
A is the Arrhenius factor.
Ea is the activation energy.
R is the general gas constant.
T is the temperature.
- At different temperatures:
<em>ln(k₂/k₁) = Ea/R [(T₂-T₁)/(T₁T₂)]</em>
k₂ = 3k₁ , Ea = ??? J/mol, R = 8.314 J/mol.K, T₁ = 294.0 K, T₂ = 308.0 K.
ln(3k₁/k₁) = (Ea / 8.314 J/mol.K) [(308.0 K - 294.0 K) / (294.0 K x 308.0 K)]
∴ ln(3) = 1.859 x 10⁻⁵ Ea
∴ Ea = ln(3) / (1.859 x 10⁻⁵) = 59.077 kJ/mol.
