Answer:
Thus, to calculate the stoichiometry by mass, the number of molecules required for each reactant is expressed in moles and multiplied by the molar mass of each to give the mass of each reactant per mole of reaction. The mass ratios can be calculated by dividing each by the total in the whole reaction.
Explanation: Stoichiometry is the field of chemistry that is concerned with the relative quantities of reactants and products in chemical reactions. For any balanced chemical reaction, whole numbers (coefficients) are used to show the quantities (generally in moles ) of both the reactants and products.
D. powder residues.
the police and forensic chemists usually perform a qualitative test called GPR or gun powder residue. the residue sticks to the skin.
The answers are
The age of the oldest stars
How fast distant galaxies are moving away from us
Patterns of background radiation.
Explanation:
The Astronomers calculate the age of the universe by looking for oldest stars, and by measuring the rate of expansion of the universe and back to big bang.
The Astronomers used the techniques like the age of oldest stars, how fast the distant galaxies are moving away from us, patterns of background radiation and along with the Big Bang as reference point, they estimate that the universe may be approximately 12 billion years old.
Answer:
Option D. pH= 1.3 strong acid
Explanation:
From the question given:
The hydrogen ion concentration [H+] = 0.05 M
pH = —Log [H+]
pH = —Log 0.05
pH = 1.3
Since the pH lies between 0 and 7, the solution is acidic. Since the pH value is low, the solution is a strong acid
Answer:
19.12 L
Explanation:
At STP(i.e. Standard temperature and pressure).
The volume occupied by one mole of gas = 22.4 L
The pressure = 1 atm
The temperature = 273 K
Thus, since 1 mole of gas = 22.4 L;
Then 0.853 moles of N2 gas will occupy:
= (0.853 moles of N2 gas × 22.4 L)/ 1 mole of N2 gas
= 19.12 L
