Answer:
A barometer is an instrument used to measure air pressure and track weather systems. The most common unit of measurement used in barometers is the millibar (mb).
Explanation:
As Fire needs oxygen to burn, Carbon Dioxide Covers the fire like an blanket and cuts the contact of fire to the oxygen present in the air, So Fire stops burning.That is why Carbon Dioxide is Considere as the best Fire Extinguisher.
There are many pros in using steel. Steel is tensile. It has a high strength to weight ratio which means it has high strength per unit mass. So no matter how large the overall structure is, the steel sections will be small and lightweight, unlike other building materials. Also, steel is very durable. Structural steel structures can withstand external pressures such as earthquakes, thunderstorms, and cyclones.
<u>Given:</u>
Mass of Ba = 1.50 g
Mass of H2O = 100.0 g
Initial temp T1 = 22 C
Final Temp T2 = 33.1 C
specific heat c = 4.18 J/g c
<u>To determine:</u>
The reaction enthalpy
<u>Explanation:</u>
The heat released during the reaction is:
q = - mc(T2-T1) = - (100+1.5) g *4.18 J/g C * (33.1-22) C = -4709.4 J
# moles of Ba = Mass of Ba/Atomic mass of Ba = 1.5 g/137 g.mol-1 = 0.0109 moles
ΔH = q/mole = - 4709.4 J/0.0109 moles = - 432 kJ/mol
Ans : The enthalpy change for the reaction is -432 kJ/mol
The number 345,000 has 3 significant figures because the trailing zeros are not significant since there's no decimal point.
<h3>What is significant figures?</h3>
Significant figures of a number in positional notation are digits in the number that are reliable and necessary to indicate the quantity of something.
Also significant figures can be defined as, the number of digits in a value, often a measurement, that contribute to the degree of accuracy of the value.
Examples of significant figures;
- 405 = 3 significant figures
- 405000 = 3 significant
- 0.040500 = 5 significant figures
<u>Note:</u> leading zeros are not significant but trailing zeros, which are zeros at the end of a number, are significant only if the number has a decimal point.
345,000 = 3.45 x 10⁵ (3 significant figures)
Thus, the number 345,000 has 3 significant figures because the trailing zeros are not significant since there's no decimal point.
Learn more about significant figures here: brainly.com/question/24491627
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