Answer: hydroxide ions
Explanation:
According to the Arrhenius concept, an acid is a substance that ionizes in the water to give hydronium ion or hydrogen ion and a bases is a substance that ionizes in the water to give hydroxide ion .
According to the Bronsted Lowry conjugate acid-base theory, an acid is defined as a substance which donates protons and a base is defined as a substance which accepts protons.
According to the Lewis concept, an acid is defined as a substance that accepts electron pairs and base is defined as a substance which donates electron pairs.
As KOH can give hydroxide ions on dissociation , it is considered as arrhenius base.

Answer: 317 joules
Explanation:
The quantity of heat energy (Q) gained by aluminium depends on its Mass (M), specific heat capacity (C) and change in temperature (Φ)
Thus, Q = MCΦ
In this case,
Q = ?
Mass of aluminium = 50.32g
C = 0.90J/g°C
Φ = (Final temperature - Initial temperature)
= 16°C - 9°C = 7°C
Then, Q = MCΦ
Q = 50.32g x 0.90J/g°C x 7°C
Q = 317 joules
Thus, 317 joules of heat is gained.
Given:
Mass, m = 51.1 g
Volume, V = 6.63 cm³
By definition,
Density = Mass/Volume
= (51.1 g)/(6.63 cm³)
= 7.7074 g/cm³
In SI units,
Density = (7.7074 g/cm³)*(10⁻³ kg/g)*(10² cm/m)³
= 7707.4 kg/m³
Answer: 7.707 g/cm³ or 7707.4 kg/m³
Answer:
Double replacement
Precipitation reaction
Explanation:
You have the reaction:
REACTANTS PRODUCTS
BaCl₂ (aq) + Na₂SO₄ (aq) ⇒ 2NaCl (aq) + BaSO₄(s)
The general form of a double replacement reaction is the following:
AB + CD ⇒ CD + AB
The reactants basically, exchanged partners. In the case of your problem, Barium(Ba) and Sodium(Na) switched places. So this makes it a double-replacement reaction.
Now how do I know it is a precipitation reaction. A precipitation reaction occurs when two solutions combine and salt is formed. Salt is solid, so how do I know that's what occured? Look at your equation again:
BaCl₂ (aq) + Na₂SO₄ (aq) ⇒ 2NaCl (aq) + BaSO₄(s)
aq means aqueous (liquid)
s means solid
If you look at the product formed in the reaction, from two solutions, it formed a solid. So this is your clue as to why it is a precipitation reaction.