Answer : The correct option is, (A) the copper must have combined with another substance.
Explanation :
According to the question, when a sample of copper powder is heated in an evaporating dish by using Bunsen burner then the mass of the powder in the evaporating dish increases after heating that means the copper powder will be combined with the another substance.
If the mass of powder in the evaporating dish is decreases after the heating then the copper powder must have lost some matter.
The given option C and D are wrong statements because the hot copper is less dense than the cold copper and as we know that the density is directly proportional to the mass of a substance that means the hot copper weighs less than cold copper.
Hence, the correct option is, (A) the copper must have combined with another substance.
13/1570
equation for molarity = moles of solute / litres of solution
Molarity = 6.5/785=13/1570
Answer:
= 3.78 g H₂O
Explanation:
2C₂H₆ + 3O₂ => 4CO₂ + 6H₂O
2.1g C₂H₆ = 2.1g/30.0 g/mol = 0.07 mole ethane
3.68g O₂ = 3.68g/32 g/mol = 0.115 mole oxygen
Limiting Reactant:
A quick way to determine limiting reactant is to divide moles of reactant by its respective coefficient in the balanced molecular equation. The smaller value is the limiting reactant.
moles ethane = 0.07 mole / 2 (the coefficient in balanced equation) = 0.035
moles oxygen = 0.115 mole / 3 (the coefficient in balanced equation) = 0.038
Since the smaller value is associated with ethane, then ethane is the limiting reactant and the problem is worked from the 0.07 moles of ethane in an excess of O₂.
From the equation stoichiometry ...
2 moles C₂H₆ in an excess of O₂ => 6 moles H₂O
then 0.07 mole C₂H₆ in an excess of O₂ => 6/2(0.07 moles H₂O = 0.21 mole
Converting to grams of water produced
= 0.21 mole H₂O X 18 g/mol = 3.78 g H₂O
Answer:
It's Chromium , I guess
Explanation:
chromium and Copper is some kind of special in
the complete electronic structure of an element
Answer:
The answer to your question is 6
Explanation:
Data
Cu + 2AgNO₃ ⇒
To find the answer, count the number of each element in the reactants
Element Quantity
Copper 1
Silver 2
Nitrogen 1
Oxygen 6
Then, in the products, there must be 6 oxygens so in the products there must be 6 oxygens so the reaction is balanced.