Calcium-49, a radioactive isotope, has a half-life of 9 minutes. If an 80-gram sample of the isotope decays for 27 minutes, how many grams of the original sample remain?
Select one:
a. 60
b. 10
c. 40
d. 20
explain why a mixture is used as the electrolyte??
Answer:
You need a mixture of positive and negative ions
Explanation:
A mixture is used as the electrolyte because a mixture of positive and negative ions are needed.
What is a Mixture?This consists of two or more chemical substances which aren't chemically bonded together.
Electrolyte on the other hand conducts electricity when dissolved with the help of the mixture of positive and negative ions.
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I need help please !!!
(01.05 MC)
Two changes are described below.
A. Ice melts to form water.
B. Sugar cubes dissolve in hot coffee.
Which statement is true about the two changes?
Answer:
A is it
Explanation:
How many moles of H2O2 are produced in the production of hydrogen peroxide when 13 grams of oxygen are used
What is the role of flagella?
Answer:
a motility organelle that enables movement and chemotaxis
Explanation:
pls mark brainlist
The materials are carried in a cell by the what
Answer:
The endoplasmic reticulum
Help me please i am so confused Find The Masses
Aluminum
Copper
Iron
Lead
How many molecules of sodium nitrate are produced when 40 g of sodium azide, NaN3, react with oxygen?
a
3.7x10^23
b
9.2x10^22
c
1.85x10^23
d
6.02x10^23
A pure substance __________ . must be an element. can be separated into simpler substances by physical means. has different chemical and physical properties depending on its source. can be separated into simpler substances by chemical means.
Answer:
a pure substance has different chemical and physical properties depending on its source
Identify the solution that is likely to have the greatest concentration of H . Please choose the correct answer from the following choices, and then select the submit answer button. Answer choices orange juice ammonia pure water bleach blood
From what we know, we can confirm that the solution that is likely to have the greatest concentration of H+ is orange juice.
This has to do with the effects of H+ in a substance. The presence of hydrogen ions causes the substance to be more acidic, and the higher the concentration the higher the acidity of the substance. Since orange juice is the only acidic solution listed, we can know it will have the highest concentration of H+ ions.
Therefore, due to its acidic nature, we can confirm that the solution that is likely to have the greatest concentration of H+ is orange juice.
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An event happens that decreases the number of earthworms, spiders, and insects in an area. How would you expect the event to affect to the number of long-billed curlews in the same area? (1 point) O It would not be affected. O It would stay the same. 0 It would increase. It would decrease.
Long-billed curlews feed on insects and worms mainly. Thus, their population will drastically reduce if there is a decrease in their food availability.
Factors affecting the population of organismsOne of the factors that affect the population size of a species is food availability.
Inadequate food increases intraspecies competition and results in more deaths. This leads to a reduction in the population size.
Long-billed curlews are a species of bird that feeds on insects and worms when inland. If an event leads to a decrease in the number of earthworms, spiders, and insects in an area, this will greatly reduce the population of long-billed curlews.
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Organisms that live in the water (ocean, rivers, intertidal zones) must be adapted for changing conditions. Describe at least one (1) adaptation that organisms living in an aquatic ecosystem might have and how it helps the organism to survive.
One adaptation that organisms living in an aquatic ecosystem might have is the ability to regulate their salt concentration.
What are organism?Organisms are living species that live on the planet earth.
There are types of organisms categorized by the environment they live.
Organism that can survive only in water is called an aquatic organism.
We have,
One adaptation that organisms living in an aquatic ecosystem might have is the ability to regulate their salt concentration.
Aquatic environments can have varying levels of salinity, and some organisms need to maintain a specific salt concentration in their bodies to survive.
For example, marine fish have kidneys that can produce very concentrated urine to prevent them from losing too much salt in their surroundings, while freshwater fish have specialized cells in their gills that actively pump salt out of their bodies to maintain the appropriate balance.
Similarly,
Some marine invertebrates, such as crabs and mussels, can regulate the amount of salt they take in by actively transporting ions across their gills or other specialized structures.
This adaptation helps the organism to maintain the proper fluid balance and avoid dehydration or over-hydration, which can be lethal.
Thus,
One adaptation that organisms living in an aquatic ecosystem might have is the ability to regulate their salt concentration.
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A green powder was placed into a beaker of water. After it was stirred the water looked cloudy and lumps of powder could still be seen. Has a solution been formed? Explain your answer?
Answer:
it make poisionus police come and took away
what is marble formed from A. obsidian B. granite C. limestone
Answer:
I'm pretty sure its C. limestone.
A compound has a percent composition of 15.24% sodium (molar mass
= 22.99 g/mol), 52.95% bromine (molar mass = 79.90 g/mol), and 31.81%
oxygen (molar mass = 16.00 g/mol). Assuming that the mass of the com-
pound is 100 g, what is the compound's empirical formula?
Show all your work. Please use correct formatting for subscripts and exponents.
The math formula editor makes it easier to show work.
This problem is providing us with the percent composition of a compound containing sodium, bromine and oxygen. Thus, the empirical formula is required and found to be NaBrO₃.
Empirical formulasIn chemistry, empirical formulas are used in order to figure out the minimum whole-number representation of a molecular formula, which contains the actual number of atoms.
Thus, we start determining it by assuming the given percentages as masses and calculating the moles with the atomic mass of the involved elements:
[tex]n_{Na}=\frac{15.24}{22.99}=0.700 \\\\n_{Br}=\frac{52.95}{79.90} =0.663\\\\n_O=\frac{31.81}{16.00}=1.99[/tex]
Next, we divide by the 0.633 as the smallest number of moles in order to determine their subscripts in the chemical formula:
[tex]Na:\frac{0.700}{0.663}=1\\ \\Br:\frac{0.663}{0.663}=1\\ \\O=\frac{1.99}{0.663} =3[/tex]
Hence, the empirical formula turns out to be NaBrO₃.
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A clasping handshake may be used as an analogy for an enzyme-catalyzed reaction because it represents the specific manner in which an enzyme ________.
Answer:
binds to substrate
Explanation:
Dominique goes to the doctor for bone aches. The doctor tells him
that Vitamin D helps his body take in the Calcium for his bones.
Explain why the doctor tells Dominique to do more outdoor activities.
Answer:
sun gives you vitamin D
Explanation:
Our body creates vitamin D from direct sunlight on our skin when we're outdoors.
Coryell walks 11 km south, and then turns east and walks 13 km. What is his
distance?
Answer:
its 24 cuz 13 + 11 =24. you're still walking 24 km in all. your going _|
What happens to the carbon dioxide that the alveoli receive from the blood?
Answer:
it is then exhaled
Explanation:
Carbon dioxide passes from the blood into the alveoli and is then exhaled.
Which statement best describes the movement of energy?.
How many grams of Al2O3are present in 7.1 x 10^22 molecules of Al2O3?
Answer:
13.4g
Explanation:
we know that:
1 mole = 6.02 × 10²³ atoms
make the unknown number of moles = x
x = 7.1 × 10²² atoms
putting them both together:
1 mole = 6.02 × 10²³ atoms
x = 7.1 × 10²² atoms
Cross multiply:
6.02 × 10²³ x = 7.1 × 10²²
divide both sides by 6.02 × 10²³
[tex]x = \frac{7.1 \times 10²² }{ 6.02 × 10²³} [/tex]
[tex]x = \frac{71}{602} [/tex]
we now have the number of moles of Al₂CO₃
to calculate the grams (mass):
[tex]moles = \frac{mass}{relative \: formula \: mass} [/tex]
[tex]mass = moles \: \times \: relative \: formula \: mass[/tex]
add up all of the atomic masses of Al₂CO₃ to calculate relative formula mass:
(27 × 2) + 12 + (16 × 3) = 114
the grams (mass) of Al₂CO₃:
[tex] \frac{71}{602} \times 114 = 13.4g[/tex]
Why must a solution of naoh be standardized using a primary standard, such as khp?.
Which of the following equations represents a nuclear charge?
Select one:
a. A
b. B
c. C
d. D
Answer:
C
Explanation:
The reaction represents transmutation, which is a nuclear reaction where electrons are transferred.
Another question. What is an example of a chemical change?
Answer:
Yellowing of leaves
Explanation:
Involves the colour change in leaves whereby less amount of chlorophyll is produced
Answer:
burning, cooking, milk becoming curd, rusting of iron
How does mixing hydrogen peroxide and water test the reactivity of catalase?.
Hydrogen peroxide is not the chemical causing the reaction.
Chemical ReactionGenerally,Catalyses is an enzyme which breaks H2O2 into H2O and O2. there will be no reaction if we combine H2O with H2O2,
H2O2 receives dissolved in water except displaying any reaction. So they are used as bad manipulate in the test.
Therefore, it shows that hydrogen peroxide is not the chemical causing the reaction
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PLS HELP MEEEEEEEEEEEEEE WITH SCIENCEEEEEEEEEE
Answer:
I believe this is a measuring cylinder? and i think the volume is 35cm^3
Explanation:
hope this helps!
how fast is a motor cycle going that travels 6 miles in 4 minutes
Answer: 60 minutes per hour, sixty miles per hour, therefore, one mile per minute.
Explanation:
Help!! Hurry!! I will mark brainliest if you get it correct. NO SPAM!!!!!!
Write the alpha decay equation for the following isotope:
211/84 PO
Answer:
216/84 Po + 4/2 He a
Explanation:
Answer:
Problem: Polonium-210, 210Po, decays to lead-206, 206Pb, by alpha emission according to the equation 21084Po → 20682Pb + 42He
Explanation:
What adaptation’s do swallowtail possess?
Plz it’s urgent
4 items being divided equally among 3 people
The decomposition of A to B is a first-order reaction with a half-life of 32.8 min:
A → 2B
If the initial concentration of A is 0.595 M, how long will it take for the concentration of A to decrease by 10.4 %?