Answer:
the answer should be B because elements do not tranform into other elements in a chemical reaction
am I right please?
Given the length of each side of a cube and its mass, the density can be obtained which can then help identify the type of material it's made of. This is because density is a unique and intrinsic property of materials. For this problem, the density is determined to be 10g/cm^3. Looking at a table of densities, the metal is most likely actinium, which has an exact density of 10 g/cm^3.
Answer:
Percentage mass of copper in the sample = 32%
Explanation:
Equation of the reaction producing Cu(NO₃) is given below:
Cu(s)+ 4HNO₃(aq) ---> Cu(NO₃)(aq) + 2NO₂(g) + 2H₂O(l)
From the equation of reaction, 1 mole of Cu(NO₃) is produced from 1 mole of copper. Therefore, 0.010 moles of Cu(NO₃) will be produced from 0.010 mole of copper.
Molar mass of copper = 64 g/mol
mass of copper = number of moles * molar mass
mass of copper = 0.01 mol * 64 g/mol = 0.64 g
Percentage by mass of copper in the 2.00 g sample = (0.64/2.00) * 100%
Percentage mass of copper in the sample = 32%
Answer:
0.24 mol/L.
Explanation:
- Ca(OH)₂ dissociates in solution according to the equation:
<em>Ca(OH)₂ → Ca²⁺ + 2OH⁻.</em>
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Every 1.0 mol of Ca(OH)₂ dissociates to give 2.0 moles of OH⁻.
∴ The no. of moles of OH⁻ produced from 0.06 mol of Ca(OH)₂ = (2 x 0.06 mol) = 0.12 mol.
<em>∴ [OH⁻] = no. of moles / V of the solution</em> = (0.12 mol)/(0.5 L) = <em>0.24 mol/L.</em>
