Answer:
A = 679.2955 ppm
Explanation:
In this case, we already know that 64Cu has a half life of 12.7 hours. The expression to use to calculate the remaining solution is:
A = A₀ e^-kt
This is the expression to use. We have time, A₀, but we do not have k. This value is calculated with the following expression:
k = ln2 / t₁/₂
Replacing the given data we have:
k = ln2 / 12.7
k = 0.0546
Now, let's get the concentration of Cu:
A = 845 e^(-0.0546*4)
A = 845 e^(-0.2183)
A = 845 * 0.8039
A = 679.2955 ppm
This would be the concentration after 4 hours
Answer: 1.14
Explanation:

To calculate the molarity of acid, we use the equation given by neutralization reaction:

where,
are the n-factor, molarity and volume of acid which is 
are the n-factor, molarity and volume of base which is NaOH.
We are given:

Putting values in above equation, we get:

To calculate pH of gastric juice:
molarity of
= 0.072
![pH=-log[H^+]](https://tex.z-dn.net/?f=pH%3D-log%5BH%5E%2B%5D)

Thus the pH of the gastric juice is 1.14
<h3>
Answer:</h3>
1.1 mol Ne
<h3>
General Formulas and Concepts:</h3>
<u>Math</u>
<u>Pre-Algebra</u>
Order of Operations: BPEMDAS
- Brackets
- Parenthesis
- Exponents
- Multiplication
- Division
- Addition
- Subtraction
<u>Chemistry</u>
<u>Atomic Structure</u>
- Avogadro's Number - 6.022 × 10²³ atoms, molecules, formula units, etc.
<u>Stoichiometry</u>
- Using Dimensional Analysis
<h3>
Explanation:</h3>
<u>Step 1: Define</u>
[Given] 6.5 × 10²³ atoms Ne
[Solve] moles Ne
<u>Step 2: Identify Conversion</u>
Avogadro's Number
<u>Step 3: Convert</u>
- [DA] Set up:

- [DA] Divide [Cancel out units]:

<u>Step 4: Check</u>
<em>Follow sig fig rules and round. We are given 2 sig figs.</em>
1.07938 mol Ne ≈ 1.1 mol Ne
Answer:
The absorbance of the solution is 0.21168.
Explanation:
Given that,
Wavelength = 500 nm
Molar absorptivity = 252 M⁻¹ cm⁻¹
Number of moles = 0.00140
Volume of solution = 500.0 mL
Length = 3.00 mm
We need to calculate the molar concentration
Using formula of the molar concentration

Where, N = number of moles
V = volume
Put the value into the formula


We need to calculate the absorbance of the solution
Using formula of absorbance

Put the value into the formula


Hence, The absorbance of the solution is 0.21168.
Answer:
I think qs. "A" the net force acting on the book by gravity is down..