<span>0.298 M
The balanced equation for the reaction is
HCl + NaOH = H2O + NaCl
So for every mole of NaOH used, one mole of HCl is neutralized. So let's determine how many moles of NaOH we used. That will simply be the volume (in liters) of solution multiplied by the molarity. So
0.0493 L * 0.151 mol/L = 0.0074443 mol
Because of that 1:1 ratio, we now know that 0.0074443 moles of HCl was in the sample. Since molarity is moles per liter, a little division will give us the molarity of the HCl solution. So
0.0074443 mol / 0.025 L = 0.297772 mol/M = 0.297772 M
Rounding to 3 significant figures gives 0.298 M.</span>
Answer:
1. 2090 J
2. 113,000J
3. 33,900J
4. -209.2 J
5. 2g
Explanation:
Note: specific heat capacity of water is 4.184 J/g°C.
1. The amount of heat can be calculated using the formula:
Q = m × c × ∆T
Q = 25 × 4.184 × (30 - 10)
Q = 104.6 × 20
Q = 2092 J
Q = 2090 J (nearest tens)
2. This question can be solved using the latent heat of vaporization of water. The latent heat of vaporization of a substance is the amount of heat required to convert a unit gram of a liquid into vapor without a change in temperature. The latent heat of vaporization of water per gram is:
2257 J/g
For 50grams of water, amount of heat that will be required will be: 50 × 2260
= 113,000J
3. For 15g of water, the amount of heat will be 15 × 2260 (latent heat of vaporization)
= 33,900J
4. Q = m × c × ∆T
Q = 5 × 4.184 × (40 - 50)
Q = 20.92 × (-10)
Q = -209.2 J
5. Q = m × c × ∆T
84 = m × 4.184 × (35 - 25)
84 = m × 4.184 × 10
84 = 41.84m
m = 84/41.84
m = 2.0076
m = 2g
Assume that your electrical power company gets its energy from a hydroelectric dam. Outline all of the energy changes that occurred from the falling water that turned the generators at the dam to the hot air that was produced from your hair dryer this morning.
Answer:
A Scientific Law
Explanation:
'When a substance goes through a chemical change the amount of mass and matter cannot be created nor destroyed.' This a statement of The Law of Conservation of Mass. This Scientific Law is simply titled as a law because every time experimented, the results are predictable and is natural occurrence.
As we know that,
1 mm Hg = 1 torr
So,
745 mm Hg = X
X = (745 mm Hg × 1 torr) ÷ 1 mm Hg
X = 745 torr
Also,
1 mm Hg = 133.325 Pa
So,
745 mm Hg = X
X = (745 mm Hg × 133.325 Pa) ÷ 1 mm Hg
X = 99327 Pa
Result:
Option-A (745 torr) is the correct answer.
