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lubasha [3.4K]
3 years ago
13

Please Help Me (Science)

Biology
1 answer:
Nostrana [21]3 years ago
3 0
Did you get the answers to these?

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If the half-life of a radioactive atom is 3,500 years. How old is the substance if the parent-daughter ratio is 1:127?
balu736 [363]

Answer:

2.447 × 10⁴ years

Explanation:

Step 1: Given data

  • Half-life of the radioactive atom (t1/2): 3,500 years
  • Parent-daughter ratio ([A]/[A]₀): 1:127 (1/127)

Step 2: Calculate the rate constant

Radioactive decay follows first-order kinetics. We can calculate the rate constant (k) using the following equation.

k = ln2 / (t1/2) = ln2 / 3,500 y = 1.980 × 10⁻⁴ y⁻¹

Step 3: Calculate the time elapsed (t)

For first-order kinetics, we will use the following expression.

ln ([A]/[A]₀) = -k × t

t = ln ([A]/[A]₀)/ (-k)

t = ln (1/127) / (1.980 × 10⁻⁴ y⁻¹) = 2.447 × 10⁴ y

3 0
3 years ago
Define electronegativity, and explain the difference between electronegativity and electron affinity. describe in general how th
Helga [31]

Electron Affinity is not far different from Electronegativity. It’s just that Electronegativity is the impulse of an atom to attract a shared pair of electrons (or electron density) towards itself and is  much more often associated with molecules rather than each atom and the values could vary to some degree, although a single value is commonly used for most calculations in inorganic chemistry whilst Electron affinity is a fixed value of an individual atom. 
4 0
4 years ago
Mosquito repellent is sprayed on one arm and the other arm is not sprayed. The number
levacccp [35]

Answer:

Dependent variable: Number of bug bites

Independent variable: Sprayed arm

Control group: Arm not sprayed.

Experimental group: Sprayed arm

Explanation:

If you know the definitions for the independent variable, dependent variable, control and experimental group in a problem than it would be less complicated to figure out what they are in any given example. So, here are the definitions:

Independent variable: the factor that you change

Dependent variable: the factor that is measured

Control group: the factor that is kept the same

Experimental group: the group in an experiment that receives the variable being tested

I had this had a question about this last week and got stumped im sure if this will help you? but I do hope it does and im sure exactly what the entire question is so.... Good Luck!

4 0
3 years ago
7. Calculate the density of a liquid with a volume of 13 mL and a mass of 6.94 grams. Round your
Masja [62]

Answer:

Density = mass/volume = 57g/4.2 mL ≈ 13.6 g/mL

Explanation:

Mass = 57 g                              Volume = 4.2 mL

The density of mercury is ⇒ 13.6 g/cm3.

Trust me I got it wrong and it gave me this. I just did the instruction.

6 0
3 years ago
Which substance is considered a building block for all living things?
adelina 88 [10]
DNA is considered the building blocks of life.
3 0
4 years ago
Read 2 more answers
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