To answer the questions,
(1) Activation energy is the amount of energy that is needed for the reaction to proceed, converting the reactant to products. The answer is letter B.
(2) The rate of chemical reaction normally increases as the reactant concentration is increased. The answer is letter C.
Answer:
3 Cu²⁺(aq) + 2 PO₄³⁻(aq) ⇒ Cu₃(PO₄)₂(s)
Explanation:
Let's consider the molecular equation between aqueous copper(II) chloride and aqueous sodium phosphate.
3 CuCl₂(aq) + 2 Na₃PO₄(aq) ⇒ 6 NaCl(aq) + Cu₃(PO₄)₂(s)
The complete ionic equation includes all the ions and insoluble species.
3 Cu²⁺(aq) + 6 Cl⁻(aq) + 6 Na⁺(aq) + 2 PO₄³⁻(aq) ⇒ 6 Na⁺(aq) + 6 Cl⁻(aq) + Cu₃(PO₄)₂(s)
The net ionic equation includes only the ions that participate in the reaction (not spectator ions) and insoluble species.
3 Cu²⁺(aq) + 2 PO₄³⁻(aq) ⇒ Cu₃(PO₄)₂(s)
The equation for this reaction is
This means that for every mole of magnesium consumed, 1 mole of magnesium oxide is produced.
So, the answer is <u>0.094</u> moles.
The substance has the specific heat capacity of steel and is therefore probably steel.
Let the specific heat of the unknown lump of substance be 
.
Energy Exchange = Specific Heat ⨯ Mass ⨯ Temperature Change
Energy the Hot Lump Lost = Energy the Cold Water Gained
Water has a specific heat of 
and a density of 
. 25.0 milliliters of water thus has a mass of 25.0 grams.
Steel has a specific heat of approximately 
. This substance is thus <em>probably </em>steel.
