Answer:
1 gram of H2 will be produced from 12 grams of Mg.
Explanation:
According to Stoichiometry, 0.5 moles of Mg are present. 1 mole of Mg produces 1 mole of H2, so 0.5 moles of Mg will produce 0.5 moles of H2. Multiplying molar mass of H2 i.e. 2 gram/mole with 0.5 moles, we can find the mass of H2 in grams which is 1 gram.
Answer:
a. 9.2
b. 4.4
c. 6.3
Explanation:
In order to calculate the pH of each solution, we will use the definition of pH.
pH = -log [H⁺]
(a) [H⁺] = 5.4 × 10⁻¹⁰ M
pH = -log [H⁺] = -log 5.4 × 10⁻¹⁰ = 9.2
Since pH > 7, the solution is basic.
(b) [H⁺] = 4.3 × 10⁻⁵ M
pH = -log [H⁺] = -log 4.3 × 10⁻⁵ = 4.4
Since pH < 7, the solution is acid.
(c) [H⁺] = 5.4 × 10⁻⁷ M
pH = -log [H⁺] = -log 5.4 × 10⁻⁷ = 6.3
Since pH < 7, the solution is acid.
Two independent variables could change at the same time, and you would not know which variable affected the dependent variable
Answer:
New experimental methods
Technological inventions
Explanation:
A scientific theory is usually not based on speculation. Scientific theories must have a solid empirical basis.
However, experimental methods are limited to the caliber of equipments available at the time in which a theory is formulated. With advancing years, more technological sophistication leads to the invention of new instruments and ultimately, the development of new experimental methods.
These innovations are likely to alter existing scientific theories as new evidences emerge, hence the answer.
Answer: Option (c) is the correct answer.
Explanation:
A limiting reagent is defined as a reagent that completely gets consumed in a chemical reaction. A limiting reagent limits the formation of products.
For example, we have given 5 mol of A and the reaction is 
Whereas when 4 mol B will react with 2 mol of A. Hence, 8 mol of B will react with 4 mol A as follows.
= 4 mol
As, the given moles of A is more than the required moles. Thus, it is considered as an excess reagent.
Hence, B is a limiting reagent because it limits the formation of products.
Thus, we can conclude that limiting reactant is the term used to describe the reactant that is used up completely and controls the amount of product that can be produced during a chemical reaction.
