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
DerKrebs [107]
2 years ago
14

the half life for strontium-90 is 29 years. how many half-lives did the sample go through at the end of 87 year​

Chemistry
2 answers:
tatuchka [14]2 years ago
6 0

= 87 : 29

= 3 half lives

Nesterboy [21]2 years ago
4 0
90 divided by 29 x 87 = 290
You might be interested in
Joan’s initial nickel (II) chloride sample was green and weighed 4.3872 g. After the dehydration reaction and removal of excess
ANEK [815]

Answer:

a) yes, it was an hydrate

b) the number of waters of hydration, x = 6

Explanation:

a) yes it was an hydrate because the mass decreased after the process of dehydration which means removal of water thus some water molecules were present in the sample.

b) NiCl2. xH2O

mass if dehydrated NiCl2 = 2.3921 grams

mass of water in the hydrated sample = mass of hydrated - mass of dehydrated = 4.3872 - 2.3921 = 1.9951 g which represent the mass of water that was present in the hydrated sample.

NiCl2.xH2O

mole of dehydrated NiCl2 = m/Mm = 2.3921/129.5994 = 0.01846 mole

mole of water = m/Mm = 1.9951/18.02 = 0.11072 mole

Divide both by the smallest number of mole (which is for NiCl2) to find the coefficient of each

for NiCl2 = 0.01846/0.01846 = 1

for H2O = 0.11072/0.01846 = 5.9976 = 6

thus the hydrated sample was NiCl2. 6H2O

4 0
3 years ago
Determine which elements or compounds are missing from the following reaction equation: hydrogen + ________ → water
Karo-lina-s [1.5K]

Answer:

Oxygen

Explanation:

Water's formula is H20. Which is two hydrogen and one oxygen.

4 0
3 years ago
What is insulin's structure?<br> a.quaternary<br> b.secondary<br> c.primary<br> d.tertiary
svetoff [14.1K]

Answer:

A

Explanation:

Quaternary structure of proteins is composed of two or more polypeptide chains. Insulin has two; one alpha  and one beta chain. The two chains are joined together by disulfide bonds at two points (at cysteines). Other examples of quaternary proteins structures are DNA polymerase and hemoglobin.

7 0
3 years ago
Click to select the correct answers. Click again to unselect answers. Leave the incorrect answers unselected.
ICE Princess25 [194]
Correct answers:
<span>Nuclear fission and fusion both affect the nucleus of an atom. 

</span><span>The final products of fission and fusion are elements that are different than the original.

</span><span>Fission occurs mostly with elements heavier than lead on the periodic table.</span>
3 0
3 years ago
Read 2 more answers
If 23.5 g of ammonia (NH3) is dissolved in 1.0 L of solution, what is the molarity?
r-ruslan [8.4K]

Answer:

1.38 M

Explanation:

Need to use the Molarity equation M=n/L

23.5g/ 17.031g/mol NH3 = 1.38 moles

1.38 moles/ 1.0 L = 1.38 M

4 0
2 years ago
Other questions:
  • What happens when Ca(NO3)2 and Na2CO3 combine?
    10·1 answer
  • 22. How many atoms are there in 344.75 g of gold nugget? a. 1.05 x 10 to the power of 24 atoms b. 1.05 x 10 to the power of 23 a
    9·1 answer
  • State one medical use of radioactive isotopes
    10·1 answer
  • What is the Molecule Geometry of a ABE3 molecule?
    14·1 answer
  • The boiling point of an aqueous 1.83 m (nh4)2so4 (molar mass = 132.15 g/mol) solution is 102.5°c. determine the value of the van
    9·1 answer
  • A student is planning an investigation of an acid-base reaction. Which of the following is not an accepted method of monitoring
    10·1 answer
  • Balance chemical equation Calcium hydroxide + carbon dioxide = calcium carbonate + water
    11·1 answer
  • ASAP PLEASE AND THANK YOU
    15·2 answers
  • At STP there is 112L of HCl gas in a container. Read the stem and answer Q. No. 1 &amp; 2.
    6·1 answer
  • Blood has a mass-volume percent of NaCl of 0.9%. What mass (g) of NaCl is present in a liter of blood
    14·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!