Given:
Q = 45.5 J, amount of heat absorbed
ΔT = 28.5 - 21.1 = 7.4 °C = 7.4 K, temperature change
c = 0.82 J/(g-°C), specific heat of CaCO₃.
Le m = the mass of the sample (g).
Then
Q = mcΔT
(45.5 J) = (m g)*(0.82 J/(g-°C))*(7.4 °C)
m = 45.5/(0.82*7.4) = 7.4984 g
Answer: 7.5 g (nearest tenth)
Answer
The elements in increasing order of atomic radius: oxygen, carbon, aluminum, potassium
Explanation:
The distance from the center of the nucleus to the outermost shell of the electron is known as the atomic radius of an element. The atomic radius decreases rightward along each period (row) of the table due to the increase in effective nuclear charge (the charge of the nucleus equal to the number of protons). Across a period, electrons are added to the same energy level and the increasing number of protons causes the nucleus to exert more pull on these electrons, which makes the atomic radius smaller. Atomic radius increases down each group (column) of the periodic table because of the addition of electrons to higher energy levels, which are further away from the nucleus and the pull of nucleus weakens. Another reason for the increase in atomic radius is the electron shielding effect, which is the reduction of the attractive force between a nucleus and its outer electrons due to the blocking effect of inner electrons
While moving from left to right in the second period, c arbon comes before oxygen and so oxygen will have a smaller atomic radius than carbon. While moving down the periodic table, al uminum comes before potassium even if they are not in the same period. So aluminum 's atomic radius will be smaller than that of potassium but bigger than that of carbon and oxygen.
(hope that helps can i plz have brainlist it will make my day :D hehe)
Answer: This is true because kinetic energy depends on speed. If there's no speed, then there is no kinetic energy.
Answer:
Closed packet together and they only can vibrate.
Explanation: Solids can have a crystalline or amorphous structure.
<span>85% ethanol | 25% ethanol | 50% ethanol
x | y | 20 gal
use x and y because you don;t know how much she needs.
0.85x | 0.25y | 20(0.5)
85% is 85/100 or 0.85, and you need that much of x, same goes for the 25% and 50% mixtures so now you can make up 2 equations
1) x + y = 20 2) 0.85x + 0.25y= 10 (you get 10 when you multiply 20 by 0.5) now you can solve for x or y using substitution.
first rewrite 1) in terms of x or y: x+ y= 20 ----> y= 20 - x now you can substitute 20- x for y in the second equation.. 0.85x + 0.25y= 10 0.85x + 0.25(20-x)= 10 distribute here..(0.25 * 20 and 0.25 * (-x) ) 0.85x + 5 - 0.25x = 10 combine like terms 0.6x +5 = 10 move the 5 over to the other side 0.6x= 10 -5 0.6x = 5 divide both sides by 0.6 x= 25/3 or 8.3 now you know the amount of x so you can substitue this back into the first equation to find y. 0.85x + 0.25y= 10 0.85(25/3) +0.25y= 10 85/12 + 0.25y= 10 0.25y = 10- 85/12 0.25y= 35/12 y= 35/3 or 11.6 you can check by putting these values into the euations: 1) x+ y= 20 25/3 + 35/3 =20 20= 20 good so far 2) 0.85x + 0.25y= 10 0.85(25/3) + 0.25(35/3)=10 10 = 10
so our values for x and y work
x= 25/3 and y= 35/3</span>
