The number of moles in a substance indicates the amount of the substance that contains the same number of particles as 12 g of the Carbon-12 isotope [or equivalent to 6.02 × 10²³] (which is used as a standard in the world of moles).
Now,
if 6.02 × 10²³ atoms are found in 1 mole ofsodium
then let 9.76 × 10¹² atoms are found in x
⇒ x = (9.76 × 10¹² ) ÷ (6.02 × 10²³)
= 1.619 × 10⁻¹¹ mol
Now, mass = moles × molar mass
∴ mass of Na = 1.619 × 10⁻¹¹ mol × 23 g/mol
= 3.72 × 10⁻¹⁰ g
double-displacement reaction
Explanation:
We have the chemical reaction:
Na₂S (aq) + Cd(NO₃)₂ (aq) → CdS (s) + 2 NaNO₃ (aq)
where:
(aq) - aqueous
(s) - solid
This is a double-displacement reaction because the reactants exchange atoms or group of atoms between themselves to form the products. To drive the reaction to the right, one of the products is a precipitate.
Generally we can express the double-displacement reaction as following:
AB + CD → AC + BD
Learn more about:
types of chemical reactions
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Answer:
In physics, the kinetic energy of an object is the energy that it possesses due to its motion It is defined as the work needed to accelerate a body of a given mass from rest to its stated velocity Having gained this energy during its acceleration the body maintains this kinetic energy unless its speed changes
Example:
A semi-truck travelling down the road
A river flowing at a certain speed
The DNA is identical because all of your cells came from that one cell through mitosis which gives and exact copy of the DNA. All body cells got the complete "instruction manual" for the body, but only uses the proteins needed.
Answer:
pH = 3.02
Explanation:
Acetic Acid is a weak acid (HOAc) that ionizes only ~1.5% as follows:
HOAc ⇄ H⁺ + OAc⁻.
In pure water the hydronium ion concentration [H⁺] equals the acetate ion concentration [OAc⁻] and can be determined* using the formula [H⁺] = [OAc⁻] = SqrRt(Ka·[acid]) = SqrRt(1.8x10⁻⁵ x 0.0500)M = 9.5x10⁻⁴M.
By definition, pH = -log[H⁺] = -log(9.5x10⁻⁴) = 3.02
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*This formula can be used to determine the [H⁺] & [Anion⁻] concentrations for any weak acid in pure water given its Ka-value and the molar concentration of acid in solution.