Answer:
Melting and Boiling Point Determination
The physical properties of a substance can be used to establish its purity. These properties include the melting point and boiling point. Different substances tend to have different melting and boiling points, and any pure substance will have a specific melting and boiling point.
Answer:
One
Explanation:
Trailing zeros in a number are not significant unless they follow a decimal point.
If you want to specify a different number of significant figures, you can use a decimal point.
For example,
2.0 × 10³ = two significant figures
2.00 × 10³ = three significant figures
2.000 × 10³ = four significant figure
2000. = four significant figures
Answer:
jet streams
Explanation:
THE JET STREAM Narrow bands of exceedingly high speed winds are known to exist in the higher levels of the atmosphere at altitudes ranging from 20,000 to 40,000 feet or more. They are known as jet streams.
Answer:
ΔH = -55.92 kJ
Explanation:
<u>Step 1:</u> Data given
1 mol NaOH and 1 mol HBr initially at 22.5 °C are mixed in 100g of water
After mixing the temperature rises to 83 °C
Specific heat of the solution = 4.184 J/g °C
Molar mass of NaOH = 40 G/mol
Molar mass of HBr = 80.9 g/mol
<u>Step 2: </u>The balanced equation
NaOH + HBr → Na+(aq) + Br-(aq) + H2O(l)
<u>Step 3:</u> mass of NaOH
Mass = moles * Molar mass
Mass NaOH = 1 * 40 g/mol
Mass NaOH = 40 grams
Step 4: Mass of HBr
Mass HBr = 1 mol * 80.9 g/mol
Mass HBr = 80.9 grams
Step 5: Calculate ΔH
ΔH = m*c*ΔT
ΔH= (100 + 40 + 80.9) * 4.184 * (83-22.5)
ΔH= 220.9 * 4.184 * 60.5
ΔH= 55916.86 J = 55.92 kJ
Since this is an exothermic reaction, the change in enthalpy is negative.
ΔH = -55.92 kJ
C. At some point, the land masses were connected to each other.
Explanation:
The fossils now exists far away from each other because at some point, the land masses were once connected to each other. Now, the land masses have drifted apart due to plate tectonics.
Alfred Wegener a scientist in 1912 first formulated the theory of continental drift. The theory suggests that present day land masses have moved to their present positions.
- A more refined theory of plate tectonics is now in play today and it provides a better understanding to why we can find similar features across different continents.
- The similar fossils must have formed together when the land masses were once joined together.
- Noe that the land masses are separated, the fossils species are not separated.
learn more:
Continental drift brainly.com/question/5002949
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