Answer:
1. What is the coefficient for calcium in the balanced equation?
2 Ca + 5 NaOH → 4 Na + 2 Ca(OH)2
2. The burning of 20.0 g of acetylene (C2H2) produces what mass of carbon dioxide? You must
write the equation, balance it and solve the mass-mass problem.
a. Balanced equation:
2 C2H2 + 5 O2 4 CO2 + 2 H2O
Explanation:
Answer: it is 5.5 mg
Explanation:
you have to multiply the mass value by 1000
Molar Volume is required to solve this problem. As we know that "1 mole of any gas at standard temperature and pressure occupies 22.4 L of volume". SO using this concept, we can calculate the volume of ammonia formed by reacting 54.1 L of Hydrogen gas as follow,
Explanation:
The molarity of a solution is defined like the number of moles of solute per liters of solution.
molarity = moles of solute/(volume of solution in L)
We know the volume of solution in L.
volume of solution = 0.65 L
To go from the mass of our solute in grams to moles we have to use its molar mass.
mass of NaCl = 63 g
molar mass of NaCl = 58.44 g/mol
moles of NaCl = 63 g * 1 mol/(58.44 g)
moles of NaCl = 1.078 moles
Finally we can find the molarity of the solution
molarity = moles of NaCl/(volume of solution)
molarity = 1.078 moles/(0.65 L)
molarity = 1.66 M
Answer: the molarity of the solution is 1.66 M.
Critical Thinking Questions
1. Why do you think forensic scientists are so careful that the tests they do are sensitive, reproducible, and specific? What might happen if they were less careful about this?
They have to be careful to ensure as much accuracy as possible.
2.Which type of evidence do you think is most useful in an investigation? Why?
Physical evidence would probably be most important because it is the best way to connect someone directly with that crime.
3.Why do you think that forensic scientists continue to look for class characteristics given their limitations?
Class characteristics are good in court because it provides details of different aspects of the crime.
