Answer:
2.6 kJ
Explanation:
The formula for the amount of heat (q) absorbed by the water is
q = mCΔT
1. Calculate ΔT
ΔT = 23.5 °C - 22.1 °C = 1.4 °C
2. Calculate q
q₂ = mCΔT = 500 g × 4.184 J·°C⁻¹g⁻¹ × 1.4 °C = 2900 J = 2.9 kJ
Answer: 6.71 g
Explanation: 



Limiting reagent is the reagent which limits the formation of product. Excess reagent is one which is in excess and thus remains unreacted.
Thus lithium is the limiting reagent and nitrogen is the excess reagent.
As can be seen from the balanced chemical equation, 6 moles of lithium reacts with 1 mole of nitrogen to give 2 moles of lithium nitride.
Thus 0.578 moles of lithium react with 0.096 moles of nitrogen.
6 moles of lithium give = 2 moles of lithium nitride
Thus 0.578 moles of lithium give=
of lithium nitride.
Mass of lithium nitride 
Mass of lithium nitride
=
Answer:
The heat needed to warm 25.3 g of copper from 22°C to 39°C is 165.59 Joules.
Explanation:

Where:
Q = heat absorbed or heat lost
c = specific heat of substance
m = Mass of the substance
ΔT = change in temperature of the substance
We have mass of copper = m = 25.3 g
Specific heat of copper = c = 0.385 J/g°C
ΔT = 39°C - 22°C = 17°C
Heat absorbed by the copper :

The heat needed to warm 25.3 g of copper from 22°C to 39°C is 165.59 Joules.
to calculate density you use the equation m/v. Divide the mass by the volume in order to get an object's density.
Answer:
a) [NH2]-,
b) [O]2-
c) [Cl]-
Explanation:
The conjugate base is the base member (X⁻) of a weak acid (HX). In other words, the conjugate base is the remaining substance due to the proton loss in the acid HX.
a) For NH₃, (HX; X: NH₂⁻), conjugate base is NH₂⁻. In the format, <em>[NH2]-</em>.
b) For OH⁻, (HX; X: O²⁻), conjugate base is O²⁻. In the format,<em> [O]2-</em>.
c) For HCl, (HX; X: Cl⁻), conjugate base is Cl⁻. In the format, <em>[Cl]-</em>.