Physical change - No change of matter in this phase
chemical change - All types of phase change occur here
Answer:
9.64g/mL
Explanation:
Given parameters:
Mass of the metal = 106g
Volume of cylinder = 50mL
Volume difference = 31mL - 20mL = 11mL
Unknown:
Density of the metal = ?
Solution:
To find the density of the metal, we use;
Density = 
Density = 
= 9.64g/mL
Answer:
the change in energy of the gas mixture during the reaction is 227Kj
Explanation:
THIS IS THE COMPLETE QUESTION BELOW
Measurements show that the enthalpy of a mixture of gaseous reactants increases by 319kJ during a certain chemical reaction, which is carried out at a constant pressure. Furthermore, by carefully monitoring the volume change it is determined that -92kJ of work is done on the mixture during the reaction. Calculate the change of energy of the gas mixture during the reaction in kJ.
From thermodynamics
ΔE= q + w
Where w= workdone on the system or by the system
q= heat added or remove
ΔE= change in the internal energy
q=+ 319kJ ( absorbed heat is + ve
w= -92kJ
If we substitute the given values,
ΔE= 319 + (-92)= 227 Kj
With the increase in enthalpy and there is absorbed heat, hence the reaction is an endothermic reaction.
Answer: Potassium hydroxide, KOH, is considered a <u>BASE</u> in an acid-base reaction because it <u>ACCEPTS</u> a hydrogen ion from the other reactant.
According to Brønsted–Lowry acid–base theory, Base is a specie which accepts proton (H⁺) while, Acid is a specie which donate proton.
Bases may contain a negative charge or lone pair of electrons, while, Acids contain positive charge or a neutral atom with incomplete octet.
In given statement KOH is acting as a base because it contains a negatively charged hydroxyl group which can accept proton from a acid, i.e.
KOH → K⁺ + OH⁻
Reaction of OH⁻ with any acid,
K⁺ + OH⁻ + HCl → H₂O + KCl
Bronsted - Lowry acid in the given reaction is NH₄, as it gives H⁺ ion.
<h3>What is Bronsted - Lowry acid?</h3>
According to the theory of Bronsted - Lowry, acids are those substances which gives H⁺ ion or proton in the aqueous medium.
Given chemical reaction is :
NH₄ + HPO₄²⁻ → NH₃ + H₂PO₄⁻
In the above reaction NH₄ is the Bronsted - Lowry acid as it gives H⁺ ion in the reaction and changes to NH₃ which is the conjugate base of NH₄. Whereas HPO₄²⁻ is the Bronsted - Lowry base as it accepts the H⁺ ion to form H₂PO₄⁻ which is the conjugate acid of it.
Hence, option (1) is correct, i.e. NH₄ is the Bronsted - Lowry acid.
To know more about Bronsted - Lowry acid, visit the below link:
brainly.com/question/1435076
