option A is a precise one to be selected!
Answer:

Explanation:
Hello there!
In this case, according to the given chemical reaction, it is possible for us to realize that the 46.2 kJ of energy are given per mole of reaction, which are related to 3 moles of hydrogen; Thus, we can calculate the energy per mole of hydrogen as shown below:

Now, to calculate the total energy, we convert the grams to moles of hydrogen as shown below:

Best regards!
Well, you see a certain color when a certain part of lightis reflected rather than and order by a material. For example, you see red because it was the only part of light that reflected.
Please tell me if that helped.
Answer=3
<span>Decomposition, double replacement, and synthesis are 3 types of chemical reactions.</span>
Answer:
Density of copper = 8.9 g/cm³
The density of liquid mercury is 13.6 g/cm³ which means mercury is denser than copper so copper will float on liquid mercury.
Explanation:
Given data:
weight of copper metal = 1896 g
Dimensions of block = 8.4 cm, 5.5 cm, 4.6 cm
Density of copper = ?
Will it float to the liquid mercury = ?
Solution:
Density:
Density is equal to the mass of substance divided by its volume.
Units:
SI unit of density is Kg/m3.
Other units are given below,
g/cm3, g/mL , kg/L
Formula:
D=m/v
D= density
m=mass
V=volume
volume of coper metal = 8.4 cm × 5.5 cm × 4.6 cm
volume of coper metal =212.52 cm³
d = 1896 g/ 212.52 cm³
d = 8.9 g/cm³
The density of liquid mercury is 13.6 g/cm³ which means mercury is denser than copper so copper will float on liquid mercury.