Answer:
669.48 kJ
Explanation:
According to the question, we are required to determine the heat change involved.
We know that, heat change is given by the formula;
Heat change = Mass × change in temperature × Specific heat
In this case;
Change in temperature = Final temp - initial temp
= 99.7°C - 20°C
= 79.7° C
Mass of water is 2000 g ( 2000 mL × 1 g/mL)
Specific heat of water is 4.2 J/g°C
Therefore;
Heat change = 2000 g × 79.7 °C × 4.2 J/g°C
= 669,480 joules
But, 1 kJ = 1000 J
Therefore, heat change is 669.48 kJ
Answer:
8.33mol/L
Explanation:
First, let us calculate the molar mass of of formaldehyde (CH2O). This is illustrated below:
Molar Mass of CH2O = 12 + (2x1) + 16 = 12 + 2 + 16 = 30g/mol
Mass of CH2O from the question = 0.25g
Number of mole CH2O =?
Number of mole = Mass /Molar Mass
Number of mole of CH2O = 0.25/30 = 8.33x10^-3mole
Now we can calculate the molarity of formaldehyde (CH2O) as follow:
Number of mole of CH2O = 8.33x10^-3mole
Volume = 1mL
Converting 1mL to L, we have:
1000mL = 1L
Therefore 1mL = 1/1000 = 1x10^-3L
Molarity =?
Molarity = mole /Volume
Molarity = 8.33x10^-3mole/1x10^-3L
Molarity = 8.33mol/L
Therefore, the molarity of formaldehyde (CH2O) is 8.33mol/L
Answer:
D, Li2S
Explanation:
This is because Lithium, which is in group IA of the periodic table, has a charge of +1. Sulfur will have a charge of -2 because it is in group 6A in the periodic table, which means to balance these out, there needs to be 2 lithium ions which would result in a charge of +2. With Lithium now having a charge of +2 due to having two atoms in the compound, and sulfur already having a charge of -2 as one atom, these two cancel out meaning the compound is neutral.
Human:
✧･ﾟ: *✧･ﾟ:* Answer: *:･ﾟ✧*:･ﾟ✧
✅ the first one
I WOULD APPRECIATE BRAINLIEST!
~ ₕₒₚₑ ₜₕᵢₛ ₕₑₗₚₛ! :₎ ♡
~
Atoms according to the kinetic molecular theory, are described in a solid to simply be vibrating in fixed positions, and not moving rapidly in the container. Because of this, they take a fixed volume and have fixed shape.
