Answer:
The coefficient in a balanced chemical equation indicates the mole ratio of both reactants and products.
Explanation:
For example lets consider the reation between Hydrogen and Oxygen to form water:
2H2 + O2 ----------------------- 2H2O
In this reaction, the coefficients of the balanced reaction can be transformed to Mole ratio according to Avogadro's Law which states that at standard temperature and pressure, equal volume of gases contain the same number of moles.
So the mole ratio for the above equation is the ratio of the coefficient:
2moles : 1 mole : 2 moles
A chemical change produces a new substances. Examples of chemical changes are burning a cooking egg
Answer:
4.823 x 10^-19 J
Explanation:
Energy is calculated by E = hv where h - Planck's constant in joule.s
v - frequency.
in this particular question the wave length is 4.12 x 10^-7 m. to exhaustively use this we need a relation between wave length & frequency. c=wv where C is approximately 3 x 10^8m/s
-v = c/w = 3x10^8m/s / 4.12 x 10^-7m = 7.28 x 10^14 Hz or 1/sec
now we can simply use Planck's constant in E=hv =
(6.626 x 10^-34) x (7.28 x 10^14Hz) = 4.823 x 10^-19 J.
Answer:
The equilibrium temperature of the coffee is 72.4 °C
Explanation:
Step 1: Data given
Mass of cream = 15.0 grams
Temperature of the cream = 10.0°C
Mass of the coffee = 150.0 grams
Temperature of the coffee = 78.6 °C
C = respective specific heat of the substances( same as water) = 4.184 J/g°C
Step 2: Calculate the equilibrium temperature
m(cream)*C*(T2-T1) = -m(coffee)*c*(T2-T1)
15.0 g* 4.184 J/g°C *(T2 - 10.0°C) = -150.0g *4.184 J/g°C*(T2-78.6°C)
62.76T2 - 627.6 = -627.6T2 + 49329.36
690.36T2 = 49956.96
T2 = 72.4 °C
The equilibrium temperature of the coffee is 72.4 °C
