Answer:
B
Explanation:
i think with exothermic reactions heat is released
this is what i looked up
hope this helps i took chem last year and think this is what i learned
Answer:
<em>The correct option is A) The atom has changed over the years.</em>
Explanation:
Option A is not correct because an atom does not change. It remains the same always. The structure of an atom will always contain neutrons, protons and electrons.
Scientific theories tend to change over time as new information is brought up. Novel techniques lead to more advanced experiments and results. As a result, a scientific theory is subjected to change whenever evidence is found for a new theory which challenges the older one.
The atomic theory has changed many times due to novel scientific techniques and experiments.
Answer:
103.9 g
Explanation:
First <u>we convert 54.0 g of propane (C₃H₈) into moles</u>, using its <em>molar mass</em>:
- 54.0 g ÷ 44 g/mol = 1.23 mol C₃H₈
Then we <u>convert 1.23 moles of C₃H₈ into moles of CO₂</u>, using the <em>stoichiometric coefficients</em>:
- 1.23 mol C₃H₈ *
= 3.69 mol CO₂
We <u>convert 3.69 moles of CO₂ into grams</u>, using its <em>molar mass</em>:
- 3.69 mol CO₂ * 44 g/mol = 162.36 g
And <u>apply the given yield</u>:
- 162.36 g * 64.0/100 = 103.9 g
Answer:
b. The final state of the substance is a gas.
d. The sample is initially a liquid. One or more phase changes will occur.
Explanation:
Methane has the following properties:
- Normal melting point: 90.7 K
- Normal boiling point: 111.65 K
*"Normal" refers to normal pressure (1 atm).
According to this, we can affirm:
- Below 90.7 K, methane is solid.
- Between 90.7 K and 111.65 K, methane is liquid.
- Above 111.65 K, methane is gas.
<em>A sample of methane at a pressure of 1.00 atm and a temperature of 93.1 K is heated at constant pressure to a temperature of 158 K. Which of the following are true? Choose all that apply.</em>
<em>a. The liquid initially present will solidify.</em> FALSE. The liquid will vaporize.
<em>b. The final state of the substance is a gas.</em> TRUE.
<em>c. The sample is initially a solid.</em> FALSE. The sample is initially a liquid.
<em>d. The sample is initially a liquid. One or more phase changes will occur. </em>TRUE.