Because they're not confident enough to confirm it's indeed true but they will support it for they believe it's correct.
Answer:
Option D. 230 J
Explanation:
We'll begin by calculating the temperature change of the iron. This can be obtained as follow:
Initial temperature (T₁) = 50 °C
Final temperature (T₂) = 75 °C
Change in temperature (ΔT) =?
ΔT = T₂ – T₁
ΔT = 75 – 50
ΔT = 25 °C
Thus, the temperature change of the iron is 25 °C.
Finally, we shall determine the amount of heat energy used. This can be obtained as follow:
Mass (M) = 20 g
Change in temperature (ΔT) = 25 °C
Specific heat capacity (C) = 0.46 J/gºC
Heat (Q) =?
Q = MCΔT
Q = 20 × 0.46 × 25
Q = 230 J
Thus, the amount of heat used was 230 J
Answer: Ammonia, an alkaline chemical, is used to raise the pH level (it's levels of acidity) of our hair during the colouring process. This then lifts the cuticles of the hair fibre and allows the colour to be deposited onto the cortex (the inner part of the hair protected by the cuticles). In hair coloring products, ammonium hydroxide is used to support the lightening action of hydrogen peroxide and to prepare hair to accept color pigments. Alkaline properties of ammonia raise the cuticle and allow peroxide and dye molecules to penetrate the hair shaft. (creds to the internet)
Explanation: Hope this helps! :D
Volume of H2 produced = 57.6576 L
<h3>Further explanation</h3>
Given
23.17 g Be
Required
Volume of H2
Solution
Reaction
Be(s)+H2O(g)→BeO(s)+H2(g)
mol Be :
= 23.17 g : 9 g/mol
= 2.574
From the equation, mol H2 : mol Be = 1 : 1, so mol H2 = 2.574
Volume H2(assumed at STP, 1 mol=22.4 L) :
= 2.574 x 22.4 L
= 57.6576 L
