Answer:
0.690666... g/cm^3
Explanation:
density=mass/volume. mass is 2.331 g and using the length we can determine that the volume of the cube is 3.375 cm^3. 2.331/3.375= 0.6906666....
Answer:
Manganese dioxide is a catalyst.
Explanation:
The decomposition of hydrogen peroxide into water and oxygen is a slow reaction and MnO₂ is used as a catalyst to speed up the reaction.
The role of MnO₂ (catalyst):
- Chemical reactions occur faster in the presence of a catalyst because the catalyst provides an alternative reaction pathway with a lower activation energy than the non-catalyzed mechanism.
- In catalyzed mechanisms, the catalyst usually reacts to form a temporary intermediate, which then regenerates the original catalyst in a cyclic process.
- A substance which provides a mechanism with a higher activation energy does not decrease the rate because the reaction can still occur by the non-catalyzed route.
- The catalyst does not used up in the reaction.
So, the right choice is:
Manganese dioxide is a catalyst.
Answer:
c
Explanation:
because that one will always be different from the others
Given: Acceleration (a) = 9.8 m/s², Initial velocity (u) = 0 m/s and time (t) = 120 s
To find: The distance traveled by Swati (s) =?
Solution: We shall apply 2nd kinematic equation of motion
s = ut + (1/2) at²
or, s = 0×120 + (1/2) × (9.8 m/s²) × (120s)²
or, s = 70,560 m
or, s = 7 km and 560 m
Hence, the required distance travel by her will be 7 km and 560 m.
The piece of unknown metal is in thermal equilibrium with water such that Q of metal is equal to Q of the water. We write this equality as follows:
-Qm = Qw
Mass of metal (Cm)(ΔT) = Mass of water (Cw) (ΔT)
where C is the specific heat capacities of the materials.
We calculate as follows:
-(Mass of metal (Cm)(ΔT)) = Mass of water (Cw) (ΔT)
-68.6 (Cm)(52.1 - 100) = 42 (4.184) (52.1 - 20)
Cm = 1.717 -----> OPTION C<span>
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