There are two naturally occurring isotopes of gallium: mass of Ga-69 isotope is 68.9256 amu and its percentage abundance is 60.11%, let the mass of other isotope that is Ga-71 be X, the percentage abundance can be calculated as:
%Ga-71=100-60.11=39.89%
Atomic mass of an element is calculated by taking sum of atomic masses of its isotopes multiplied by their percentage abundance.
Thus, in this case:
Atomic mass= m(Ga-69)×%(Ga-69)+X×%(Ga-71)
From the periodic table, atomic mass of Ga is 69.723 amu.
Putting the values,
Thus,
Rearranging,
Therefore, mass of Ga-71 isotope is 70.9246 amu.
Answer:
She can add 380 g of salt to 1 L of hot water (75 °C) and stir until all the salt dissolves. Then, she can carefully cool the solution to room temperature.
Explanation:
A supersaturated solution contains more salt than it can normally hold at a given temperature.
A saturated solution at 25 °C contains 360 g of salt per litre, and water at 70 °C can hold more salt.
Yasmin can dissolve 380 g of salt in 1 L of water at 70 °C. Then she can carefully cool the solution to 25 °C, and she will have a supersaturated solution.
B and D are wrong. The most salt that will dissolve at 25 °C is 360 g. She will have a saturated solution.
C is wrong. Only 356 g of salt will dissolve at 5 °C, so that's what Yasmin will have in her solution at 25 °C. She will have a dilute solution.
To solve this problem we just need to use the rule of three:
150g..................395.1J
450g................xJ
x = 450*395.1/150 = 1185,3J
450.0 g of the substance completely reacted with oxygen will produce 1.1853 kJ(<span>kiloJoule</span>)
Answer is: 1160 J of heat Is required to increase the temperature.
m(Fe) = 100 g.
∆T = 40,2 - 15 = 25,2°C.
C(Fe) = 0,46 J/g•°C.
Q = m(Fe) • C • ∆T.
Q = 100 g • 0,46 J/g•°C • 25,2°C
Q = 1160 J.
C - specific heat.
Answer:
Explanation:
Pro – Low carbon. Unlike traditional fossil fuels like coal, nuclear power does not produce greenhouse gas emissions like methane and CO2. ...
Con – If it goes wrong… ...
Pro – Not intermittent. ...
Con – Nuclear waste. ...
Pro – Cheap to run. ...
Con – Expensive to build
