Answer:
A chemical change occurs when the reactants chemical compositions have changed
Explanation:
a change in colour, change in temperature, change in smell, formation of a precipitate, or the formation of gas bubbles
Hopes this helps
Answer:
29260J
Explanation:
Given parameters:
Mass of water sample = 100g
Initial temperature = 30°C
Final temperature = 100°C
Unknown:
Energy required for the temperature change = ?
Solution:
The amount of heat required for this temperature change can be derived from the expression below;
H = m c (ΔT)
H is the amount of heat energy
m is the mass
c is the specific heat capacity of water = 4.18J/g°C
ΔT is the change in temperature
Now insert the parameters and solve;
H = 100 x 4.18 x (100 - 30)
H = 100 x 4.18 x 70 = 29260J
Answer:
0.84 mol
Explanation:
Given data:
Moles of ZnCl₂ produced = ?
Mass of Zn = 55.0 g
Solution:
Chemical equation:
2HCl + Zn → ZnCl₂ + H₂
Number of moles of Zn:
Number of moles = mass / molar mass
Number of moles = 55.0 g/ 65.38 g/mol
Number of moles = 0.84 mol
Now we will compare the moles of Zn with ZnCl₂ from balance chemical equation.
Zn : ZnCl₂
1 : 1
0.84 : 0.84
So from 55 g of Zn 0.84 moles of zinc chloride will be produced.
An acrostic poem is a type of poetry where the first, last or other letters in a line spell out a particular word or phrase.
ANSWER: B) drying paint
EXPLANATION: Car manufacturers use UV radiation to dry the paint o the vehicle. The high reflectivity of infrared radiation helps to keep the car interior cool. It also gives advantages over convection heating. It can provide both high intensity and low intensity heat and is a low cost heat source when compared in dollars per unit of energy consumed. The IR heating also doesn't penetrate deeply and apply heating only on the outer surface.
