Answer:
C. A physical change.
Explanation:
A liquid is cooled during an investigation causing it solidify.Which of the following most likely occurred?
A. Absorption of heat. NO. Heat was released.
B. A chemical change. NO. It was a physical change
C. A physical change. YES. The physical change is called solidification.
D. Formation of a new compound. NO. This would be a chemical change.
Answer:
Kernels are placed in a pan on a stove
Explanation:
Heat transfer by conduction involves the actual movement between particles of the medium. For conduction to occur, the particles must be in contact with the heating medium or the body at a higher temperatures.
For the popcorn kernels to conduct heat using the conduction heat transfer process, the kernels are placed in contact with the heat source using the frying pan. The stove is the heat source.
When put a knife in contact with fire, it is heat transfer by conduction.
<h3>
Answer:</h3>
89.88° C
<h3>
Explanation:</h3>
<u>We are given;</u>
- Mass of gold cylinder as 75 g
- specific heat of gold is 0.129 J/g°C
- Initial temperature of gold cylinder is 65°C
- Mass of water is 500 g
- Initial temperature of water is 90 °C
We are required to calculate the final temperature;
- We know that Quantity of heat is given by the product of mass, specific heat capacity and change in temperature.
<h3>Step 1: Calculate the quantity of heat absorbed by the Gold cylinder</h3>
Assuming the final temperature is X° C
Then; ΔT = (X-65)°C
Therefore;
Q = 75 g × 0.129 J/g°C × (X-65)°C
= 9.675X - 628.875 Joules
<h3>Step 2: Calculate the quantity of heat released by water</h3>
Taking the final temperature as X° C
Change in temperature, ΔT = (90 - X)° C
Specific heat capacity of water is 4.184 J/g°C
Therefore;
Q = 500 g × 4.184 J/g°C × (90 - X)° C
= 188,280 -2092X joules
<h3>Step 3: Calculate the final temperature, X°C</h3>
we know that the heat gained by gold cylinder is equal to the heat released by water.
9.675X - 628.875 Joules = 188,280 -2092X joules
2101.675 X = 188908.875
X = 89.88° C
Thus, the final temperature is 89.88° C
From the chemical equation given, one mole of CH4 yields two moles of water (H2O). If all the methane gas that is 8.9 L is combusted then the volume of water produced is the number of moles H2O times the volume of the methane gas used up, that is 8.9 L × 2 = 17.8 L of water produced.
Answer:
Overall reaction equation;
2NO(g) +Cl2(g) -----> 2NOCl (g)
Explanation:
Given
1) NO(g) + Cl2(g) → NOCl2(g)
2) NOCl2(g) + NO(g) → 2NOCl(g)
Overall reaction equation;
2NO(g) +Cl2(g) -----> 2NOCl (g)
k1= [NOCl2]
k-1= [NO] [Cl2]
k2 = [NOCl2] [NO]
Equilibrium for the first equation (reaction 1)
K= k1/k-1 = [NOCl2]/[NO] [Cl2]
Therefore
[NOCl2] = k1/k-1 [NO] [Cl2]
Rate= k2× k1/k-1 [NO]^2 [Cl2]
Rate = Koverall [NO]^2 [Cl2]
Where Koverall= k1k2/k-1
