You first need to write the balanced chemical reaction for what is going on.
Ca(OH)₂+2HCl→2H₂O+CaCl₂
After you make the balanced chemical reaction, First you find the moles of HCl used. To do this multiply 0.0375L by 0.124M to get 0.00465mol HCl. Then you multiply 0.00465mol HCl by (1mol Ca(OH)₂)/(2mol HCl) to get 0.002325mol Ca(OH)₂. Finally to find concentration of Ca(OH)₂ used you divide 0.002325mol by 0.020L to get 0.116M Ca(OH)₂.
Therefore the concentration of the unknown solution of Ca(OH)₂ was 0.116M.
I hope this helps. Let me know if anything is unclear.
D. Zinc metal (zn)
Zinc is a chemical element with atomic number 30.
Answer:
The correct answer is 0.11 mol O₂
Explanation:
The chemical equation for the reaction of acetylene (C₂H₂) with O₂ to produce carbon dioxide (CO₂) and water (H₂O) is the following:
2 C₂H₂(g) + 5 O₂(g) → 4 CO₂(g) + 2 H₂O(g)
The chemical equation is balanced : with the proper estequiometrical coefficients. According to this, 2 moles of C₂H₂ reacts with 5 moles of O₂ to give 4 moles of CO₂ and 2 moles of H₂O.
In order to calculate how many moles of O₂ are needed to produce 0.085 moles of CO₂, we multiply the 0.085 moles of CO₂ by the factor 5 moles O₂/4 moles CO₂ (because 4 moles of CO₂ are produced by 5 moles of O₂ according to the chemical equation):
0.085 moles CO₂ x (5 moles O₂/4 moles CO₂) = 0.10625 moles O₂ = 0.11 moles O₂
The correct answer among the choices given is option C. Radioactive decay is the process whereby a stable nucleus loses energy by emitting radiation. It is the spontaneous breakdown of a nucleus that results from the release of energy and matter from the nucleus.
