Answer:
The blue star is the hottest star.
Explanation:
Red stars are cooler than the sun, with surface temperatures of 3,500 K for a bright red star and 2,500 K for a dark red star. The hottest stars are blue, with their surface temperatures falling anywhere between 10,000 K and 50,000 K
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
If matter was not composed of atoms, the law definite proportions and law of multiple proportions will not hold true because compound would have random composition.
<h3>What is the law of definite proportions and law of multiple proportions?</h3>
The law of definite proportions states that all pure samples of a compound contains the same element in a fixed mass ratio.
The law of multiple proportions states that if an element combines with another element to form more than one compound, the mass of the element combines with a fixed mass of the other element in whole number multiples ratios.
Assuming matter was not composed of atoms, the law definite proportions and law of multiple proportions will not hold true because, their will be no definite ratio or composition in compounds.
The law definite proportions and law of multiple proportions are required for the atomic theory as they help prove that matter consists of definite unique particles called atoms.
In conclusion, the existence of atoms is proved true by the law definite proportions and law of multiple proportions.
Learn more about law of multiple proportions at: brainly.com/question/2624012
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Answer:
A is oxidation . B is reduction
Explanation:
A will be oxidation agent because there is gain of
electrons
B will be reducing agent because there is loss of
electrons.
Answer:
10 kg of water was added to the 20 kg of seawater to dilute it from 3% to 2%. Hope this helps!!!!!!
