Answer:
0.712 mol
Explanation:
The easiest way to do this is to use a proportion.
1 mol of copper = 63.5 grams (check this using your periodic table).
x mol of copper = 45.2 grams
1/x = 63.5 / 45.2 Cross multiply
63.5 x = 1 * 45.2 Divide by 63.5
x = 45.2/63.5
x = 0.712 mol Answer to 3 sig digs
Acid - base indicators (also known as pH indicators) are substances which change color with pH. They are usually weak acids or bases. you use them if you want to know if a solution is an acid or it it's a base
Answer:
pH = 12.22
Explanation:
<em>... To make up 170mL of solution... The temperature is 25°C...</em>
<em />
The dissolution of Barium Hydroxide, Ba(OH)₂ occurs as follows:
Ba(OH)₂ ⇄ Ba²⁺(aq) + 2OH⁻(aq)
<em>Where 1 mole of barium hydroxide produce 2 moles of hydroxide ion.</em>
<em />
To solve this question we need to convert mass of the hydroxide to moles with its molar mass. Twice these moles are moles of hydroxide ion (Based on the chemical equation). With moles of OH⁻ and the volume we can find [OH⁻] and [H⁺] using Kw. As pH = -log[H⁺], we can solve this problem:
<em>Moles Ba(OH)₂ molar mass: 171.34g/mol</em>
0.240g * (1mol / 171.34g) = 1.4x10⁻³ moles * 2 =
2.80x10⁻³ moles of OH⁻
<em>Molarity [OH⁻] and [H⁺]</em>
2.80x10⁻³ moles of OH⁻ / 0.170L = 0.01648M
As Kw at 25°C is 1x10⁻¹⁴:
Kw = 1x10⁻¹⁴ = [OH⁻] [H⁺]
[H⁺] = Kw / [OH⁻] = 1x10⁻¹⁴/0.01648M = 6.068x10⁻¹³M
<em>pH:</em>
pH = -log [H⁺]
pH = -log [6.068x10⁻¹³M]
<h3>pH = 12.22</h3>
II. sulfur (S) and carbon (C)
and
III. fluorine (F) and oxygen (O)
will form covalent bonds, so the answer will be:
e. II and III
Explanation:
To know is what type of bond is formed between atoms we need to look at the electronegativity difference between the atoms.
If the electronegativity difference is less than 0.4 there is a nonpolar covalent bond.
If the electronegativity difference is between 0.4 and 1.8 there is a polar covalent bond. (if is a metal involved we consider the bond to be ionic)
If the electronegativity difference is greater then 1.8 there is an ionic bond.
We have the following cases:
I. lithium (Li) and sulfur (S)
electronegativity difference = 2.5 (S) - 1 (Li) = 1.5 but because there is a metal involved the bond will be ionic
II. sulfur (S) and carbon (C)
electronegativity difference = 2.5 (S) - 2.5 (C) = 0 so the bond will be nonpolar covalent
III. fluorine (F) and oxygen (O)
electronegativity difference = 4 (F) - 3.5 (O) = 0.5 so the bond will be polar covalent bond.
Learn more about:
covalent and ionic bonds
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