14 The equation for the effect of heat on hydrated sodium carbonate is as shown. Na2CO3. 10H2O(s) → Na2CO3(s) + 10H2O(g)
Statements made by four students about the reaction are given.
P
Anhydrous sodium carbonate is formed.
Steam is formed.
Q
R
There is a colour change from blue to white.
S
The reaction is reversible.
Which students' statements are correct?
A
P, Q and R only
B
P, Q and S only
Q, R and S only
С
D
P Q R and S

Look at the spectrums of a star moving towards earth and a motionless star. which of these is a correct inference that can be draw from the observation of the two spectrums? (2 points) the spectrum of a motionless star is difficult to be viewed separately using oridinary telescopes. the spectrum of a motionless star is identical to the spectrum of a star which moves towards earth. the spectrum of a star shifts towards the red region when the star moves towards earth. the spectrum of a star shifts towards the blue region when the star moves towards earth.

How is energy related to the change of state represented by the model? atoms gain energy as a solid changes to a liquid. atoms gain energy as a solid changes to a gas. atoms lose energy as a solid changes to a liquid. atoms lose energy as a solid changes to a gas.

What happens to the concentration of hydronium ions as the ph of a solution increases? a. hydronium ion concentration stays the same b. hydronium ion concentration decreases c. hydronium ion concentration increases