B the atmosphere
D. gasoline
C. a carbonated soft drink (without bubbles)
Scientific investigation: The process in which scientist solve the question by using different systematic approach. It can be initiated in different ways.
Experimental Scientific investigation: The investigation in which scientist answer the question on the basis of experimental results. Experimental investigation includes both dependent and independent variables, and only one variable is tested at a time is possible.
The best example of an experimental scientific investigation is: when we placed a whole apple and apple slice under sun, and noted down how many days it will take to rot in order to compare the break down of apple slice and whole apple.
Thus, option (B) is the correct answer.
Answer:
67.1%
Explanation:
Based on the chemical equation, if we determine the moles of sodium carbonate, we can find the moles of NaHCO₃ that reacted and its mass, thus:
<em>Moles Na₂CO₃ - 105.99g/mol-:</em>
6.35g * (1mol / 105.99g) = 0.0599 moles of Na₂CO₃ are produced.
As 1 mole of sodium carbonate is produced when 2 moles of NaHCO₃ reacted, moles of NaHCO₃ that reacted are:
0.0599 moles of Na₂CO₃ * (2 moles NaHCO₃ / 1 mole Na₂CO₃) = 0.1198 moles of NaHCO₃
And the mass of NaHCO₃ in the sample (Molar mass: 84g/mol):
0.1198 moles of NaHCO₃ * (84g / mol) = 10.06g of NaHCO₃ were in the original sample.
And percent of NaHCO₃ in the sample is:
10.06g NaHCO₃ / 15g Sample * 100 =
<h3>67.1%</h3>
