I think it would be penicillin as it saved many lives in its time and ours.
Answer:
The solution is given below
Explanation:
Heat, q= mc∆T
q= 125g x 4.18 J/g∙°C x (21.18x- 24.28) °C
q= -1619.75J
NEGATIVE SIGN INDICATES THAT HEAT IS ABSORBED.
Enthalpy Change, ∆H = 1619.75 7/ 10.5 g
= 154.26 J/g
No. of moles of KBr = Mass of KBr/ Molecular Weight of KBr
=10.5g/119gmol-1
=0.088 mol
∆H= 1619.75 J/ 0.088 mol
= 18.41 kJ/mol
With all of the information given (pressure, volume, temperature, and the molar mass), we need a formula that relates this all together. The formula we need is the ideal gas law, PV=nRT. Since the pressure is defined in millimeters of mercury, we need the R value that correlates with this, which is 62.4; on top of this, we need the temperature in Kelvin - simply add 273.15 to convert from Celsius. With all of this information, simply plug-and-chug:
PV=nRT
(800)(3.7) = n(62.4)(37 + 273.15)
n = 0.1529 moles
Finally, the problem is asking the amount of air in grams. We have moles, so all we need to do is multiply that value by the molar mass.
0.1529 moles x 29 grams per mole =
4.435 grams of air
The balloon has 4.435 grams of air inside it.
Hope this helps!
Explanation:
The end goal of this question is to find density. Density can be found using the following formula:
D=m/v
D=Density
m=mass
v=volume
Therefore we need mass and volume to find density. Mass is already given in the question as 142g. All we have left is volume. When a solid is placed in water in a graduated cylinder the volume goes up. This means if you subtract the volume after the metal was placed from before it was placed, you can find the volume of the metal. Therefore the volume of the metal is 40mL-20mL=20mL. However typically, volume is found in liters so the volume should be .04L-.02L=0.02L. Now that we have volume and mass we can find density using the formula d=m/v. So 142/.02=7,100 grams per liget or 7.1 kilograms per liter. This answer seems unrealistic so I would double check with your teacher about the question.
Hope I helped, 2Trash4U
A cleaning solution with an OH⁻ concentration of 2.5 × 10⁻⁴ mol/L, has a pH of 10.4 and is basic (options b and c).
<h3>How can we determine the acidity or basicity of a solution?</h3>
- If pH < 7, the solution is acid.
- If pH = 7, the solution is neutral.
- If pH > 7, the solution is basic.
- Step 1. Calculate the pOH of the solution.
The hydroxide ion concentration is 2.5 × 10⁻⁴ mol/L.
pOH = -log [OH⁻] = log (2.5 × 10⁻⁴) = 3.6
- Step 2. Calculate the pH of the solution.
We will use the following expression.
pH + pOH = 14
pH = 14 - pOH = 14 - 3.6 = 10.4
Since pH > 7, the solution is basic.
A cleaning solution with an OH⁻ concentration of 2.5 × 10⁻⁴ mol/L, has a pH of 10.4 and is basic (options b and c).
Learn more about pH here: brainly.com/question/172153
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