1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
34kurt
2 years ago
13

Radioactive phosphorus-32 decays with a half-life of 14.0 days. A chemist obtains a fresh sample of phosphorus-32 and measures i

ts radioactivity. She then determines that to do an experiment, the radioactivity cannot fall below 25% of the initial measured value. How many days does she have to perform the experiment
Chemistry
1 answer:
solniwko [45]2 years ago
3 0

It will take 28 days to let the radioactivity fall below 25%.

<h3>What is Half Life ?</h3>

Half life can be described as the time required by the radioactive compound to reduce to half of the original value of concentration.

It is given that

Radioactive phosphorus-32 decays with a half-life of 14.0 days

25% of the initial measure at what time =?

For 50% decay the time needed is 14 days

for decay of the next 50%  of the amount left the time taken will be another 14 days

2nd half life = 25% decay of the substance = 28 days

Therefore it will take 28 days to let the radioactivity fall below 25%.

To know more about Half Life

brainly.com/question/24710827

#SPJ1

You might be interested in
Which statement about phospholipids is true?
Ira Lisetskai [31]

Answer:

3. Tails of phospholipids are hydrophobic.

Explanation:

According to the fluid mosaic model, the plasma or cell membrane contains components such as: proteins, phospholipids etc. The phospholipid forms a layer called PHOSPHOLIPID LAYER, which comprises of a phosphate head and a fatty acid (lipid) tail.

The phosphate head is HYDROPHILIC i.e. water-logging while the fatty acid/lipid tail is HYDROPHOBIC i.e. water-fearing. Hence, according to this question, it is TRUE that the tails of phospholipids are hydrophobic.

Note: Phospholipid layer, which are selectively-permeable i.e do not allow the passage of molecules, allows the passage/diffusion of small molecules like oxygen gas.

5 0
2 years ago
Read 2 more answers
Empirical formula for compound of 2.17 mol N and 4.35 mol O
balu736 [363]

Answer:

Explanation:

ratio of  moles of N and O in molecule =

N / O = 2.17 / 4.35

1/2

empirical formula = NO₂

4 0
2 years ago
You are provided with a compound fertilizer, 40-15-10.Calculate the quantity of fertilizer to add to a one hectare field supply
victus00 [196]

Answer:

a. 300 kg of Fertilizer

b. 225 kg of fertilizer

c.400 Kg of fertilizer

d.600 Kg of fertilizer

Explanation:

The percentage composition ratio of Nitrogen, Phosphorus and Potassium bag of the given fertilizer is 40:15:10.

The percentages can be expressed as fractions as follows:

For nitrogen; 40/100 = 0.4

For phosphorus; 15/100 = 0.15

For potassium; 10/100 = 0.1

To find the quantity of fertilizer required to add to a hectare to supply the given amount of nutrients, the amount to be provided is divided by the percentage or fractional compostion of each nutrient.

Quantity of fertilizer required to add to a hectare to supply;

a. Nitrogen at 120 kg/ha = 120/0.4 = 300 Kg of fertilizer

b.. Nitrogen at 90 Kg/ha = 90/0.4 = 225 Kg of fertilizer

c. Phosphorus at  60 kg/ha = 60/0.15 = 400 Kg of fertilizer

d. Potassium at 60 kg/ha = 60/0.1 = 600 Kg of fertilizer

5 0
2 years ago
What element has 47 protons in its nucleus?
sesenic [268]

Answer:

b). silver (Ag)

Explanation:

If you look at the periodic table, you just need to look at the atomic number of the element, because the atomic number tells you how many protons there are in the nucleus of the element.

But do be careful because some periodic tables have the molar mass at the top left corner, but the one I use has the atomic number at the top left corner, so make sure you look for the atomic number and not the molar mass.

5 0
3 years ago
a brick measures 25cm by 12cm by 13cm. What is the volume of the brick in cm cubed? how many milliliters of water would this bri
julia-pushkina [17]
The volume is 3900cm^3 and the bricks density is 3900 ml
5 0
3 years ago
Other questions:
  • Which of the following is formed from erosion
    9·2 answers
  • An animal that backs on a warm rock during the morning hours but retreats to the shade of the rocks during the middle of the day
    15·1 answer
  • suppose you wanted to change the rate of a chemical reaction. what might you change in the reaction? explain the factor
    13·1 answer
  • Name the following chemical compound. NaBr
    12·2 answers
  • What change could a chemist make to a reaction environment that would increase the likelihood that molecules in a reaction would
    8·1 answer
  • If fluorine 20 undergoes beta decay , what will it become ?
    15·2 answers
  • BASIC CALCULATIONS IN SPECTROSCOPY
    11·1 answer
  • sodium reacts with chlorine gas to form sodium chloride. if you have 60 L of chlorine gas at STP and 30 g of sodium, how many gr
    9·1 answer
  • Copper sulfate, when it is dissolved in water, has a blue color. When steel wool is mixed with a copper sulfate solution, the st
    12·1 answer
  • Shaila is collecting data to calculate the density of a piece of wood. First, she
    5·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!