Based on the ideal gas relation:
PV = nRT
where P = pressure ; V = volume ; T = temperature
n = number of moles; R = gas constant = 0.0821 L atm/mol-K
Step 1: Find the number of moles of O2
n = PV/RT = 1 * 3.90/0.0821*273 = 0.1740 moles
Step 2: Calculate the molecules of O2
Now, 1 mole of O2 corresponds to 6.023 * 10²³ molecules of O2
Therefore, 0.1740 moles of O2 corresponds to-
0.1740 moles of O2 * 6.023*10²³ molecules of O2/1 mole of O2
= 1.048 * 10²³ molecules of O2
A.) <span>Each molecule of hydrochloric acid, HCl, contains one atom of hydrogen and "One atom of Chlorine"
Hope this helps!</span>
Once you have constructed an effective hypothesis, the next step in the scientific inquiry process is to
test the hypothesis through experimentation. This is a great opportunity for students to start a science
notebook, if they have not yet started recording their progress.
Steps to Identifying and Conducting an Appropriate Experiment to Test a Hypothesis
1) Present Hypotheses
Make a list of all potential hypotheses to be tested.
2) Make Predictions
For each hypothesis, ask what would be true if the hypothesis were true.
3) Write the Experimental Procedure
The experimental procedure is a step-by-step recipe for the science experiment. A good
procedure contains enough detail that someone else could easily duplicate the
experiment. Once you have formed a hypothesis, you will need to develop your
experimental procedure to test whether your hypothesis is true or false.
4) Identify the Independent and Dependent Variables
The first step of designing the experimental procedure involves planning how to change
the independent variable and how to measure the impact that this change has on the
dependent variable. To guarantee a fair test when conducting the experiment, make sure
that the only thing changing is the independent variable. All controlled variables must
remain constant.
5) Design the Experiments
How can you identify an appropriate experiment that will effectively test your
hypothesis? Begin by asking yourselves, “What can I do that will give me one result if my
hypothesis is true, and a different result if my hypothesis is false?” Design at least one
possible experiment for each hypothesis. Be sure that each experiment tests only one
hypothesis.
Answer:
A = Molarity = 0.22 M
B = Molarity = 0.36 M
Explanation:
Given data:
For first solution:
number of moles = 0.550 mol
Volume of solution = 2.50 L
Molarity = ?
Molarity:
Formula:
Molarity = number of moles of solute / volume of solution in L.
Molarity = 0.550 mol / 2.50 L
Molarity = 0.22 M
For second solution:
Mass of NaCl = 15.7 g
Volume of solution = 709 mL or 709/1000 = 0.709 L
Molarity = ?
Solution:
Number of moles = mass / molar mass
Number of moles = 14.7 g/ 58.44 g/mol
Number of moles = 0.252 mol
Molarity:
Molarity = number of moles of solute / volume of solution in L.
Molarity = 0.252 mol / 0.709 L
Molarity = 0.36 M
Answer:
B. 26.00 g Fe
Atomic mass of Fe (Iron) is 55.845g