Answer: The conclusion that best support the observation is that (A CHEMICAL CHANGE took place).
Explanation:
A chemical reaction is defined as the process by which two or more substances, which are often referred to as REACTANTS, combine through bond formation or dissociation of bonds to form new PRODUCTS. In this type of reaction, a CHEMICAL CHANGE occurred because a new substance is formed as a result of the chemical reaction that took place.
There are different characteristics of a reaction which shows that a chemical change has occurred, these includes:
--> Color Change
--> Production of an odor
--> Change of Temperature
--> Evolution of a gas (formation of bubbles)
-- Precipitate (formation of a solid)
From the chemical reaction in the given question, Lithium metals reacts slowly with water to form a colourless solution of lithium hydroxide (LiOH) and hydrogen gas (H2). Here we observe that the buzzing sound of formed gas bubbles shows that a gas was given off. Therefore in conclusion, a CHEMICAL CHANGE took place.
Answer: In a compound with molecular formula ,the valency of Y and X are 2 and 3 respectively.
Explanation:
For formation of a neutral ionic compound, the charges on cation and anion must be balanced. The cation is formed by loss of electrons by metals and anions are formed by gain of electrons by non metals.
The given compound is where X and Y combine and their oxidation states or valencies are exchanged and written in simplest whole number ratios. Thus the oxidation state or valency of X is 3 and that of Y is 2.
Answer:
A: Both models represent atoms with the same atomic number.
Explanation:
The atomic number equals the number of protons.
Explanation:
The chemical reaction equation will be as follows.
As 1 mole reacts with 1 mole of
Hence, moles of = Molarity × Volume (in mL)
= 0.5 × 38.0 mL
= 0.019 mol
Moles of = Molarity × Volume (in mL)
= 0.6 × 42.0 mL
= 0.0252 mol
As moles of CuS is less than the moles of . This means that CuS is the limiting reagent.
Thus, maximum moles of CuS formed are 0.019 mol. As molar mass of CuS is 95.6 g/mol.
Therefore, maximum mass of CuS can be formed is
= 1.8164 g
Thus, we can conclude that maximum mass of CuS formed is 1.8164 g.