Answer: True
Explanation: Following are the properties that are used to identify minerals:
(1) Color
(2) Hardness
(3) Magnetism : It is the property of mineral to attract or repel with other magnetic materials.
(4) Luster : It is the property that shows the surface is reflecting light or not.
(5) Reactivity: Reactivity is also responsible to identify mineral. How the mineral is reacting with acids, bases etc helps to identify type of minerals.
Mass = 1.2 kg = 1200 grams.
Volume = mass/density = 1200 cm3.
Hope this helps!
Answer: a) 7.1 * 10^3 N; b) -880 N directed out of the curve.
Explanation: In order to solve this problem we have to use the Newton laws, then we have the following:
Pcos 15°-N=0
Psin15°-f= m*ac
from the first we obtain N, the normal force
N=750Kg*9.8* cos (15°)= 7.1 *10^3 N
Then to calculate the frictional force (f) we can use the second equation
f=P sin (15°) -m*ac where ac is the centripetal acceletarion which is equal to v^2/r
f= 750 *9.8 sin(15°)-750*(85*1000/3600)^2/150= -880 N
Answer:
(a) Most reactive 
Metal B
Metal D
Metal A
Least reactive Metal C
(b) (i) Bubbles should form very slowly
(ii) No reaction takes place
Explanation:
(a) The given metals arranged in their order of reactivity are;
Most reactive Metal B
Metal D
Metal A
Least reactive Metal C
The other of reactivity is based on the nature of their reactivity of the metals in air
(b) (i) Based on the reactivity of the metals in air, whereby metal A reacts very slowly and an oxide is formed, we have that, based on the reactivity of the metal A, when mixed with dilute hydrochloric acid, bubbles should form very slowly
(ii) Similarly, given that metal C is unreactive, we have that when small pieces of metal C are added to dilute hydrochloric acid, no reaction takes place.
Answer is C. All of the others are internal/molecular changes.
