Answer:
Hope it helps.
Explanation:
It decays by beta particle emission into xenon-131. After eight days have passed, half of the atoms of any sample of iodine-131 will have decayed, and the sample will now be 50% iodine-131 and 50% xenon-131
Heavy unstable atoms will continuously emit radiation and will undergo nuclear decay to form stable products. 25 g of americium -241 will take 39 years to decay into its 6.25 g sample.
What is radioactive decay?Heavy unstable nuclei undergo decay when they emit radiations of alpha, beta or gamma particles. After that they will form stable isotopes or other lighter nuclei after emitting these charged particles.
The time an unstable nuclei takes to decay into half of its initial amount is called half life time. The half life time of Americium -241 is 432 years. Thus half life time of 25 g of Am-241 is
= (25 × 432 )/241
= 44.81 years.
The decay constant k can be calculated as follows:
k = 0.693 /half life time
= 0.693 /44.81 yrs
= 0.015.
Now the time taken for the decay process is calculated by the following equation:
t = 1/k log (25/6.25)
= 1/0.015yr-1 log (25/6.25)
= 39 years
Hence, 5 g of americium -241 will take 39 years to decay into its 6.25 g sample.
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solve find the value of x
Answer:
50
Explanation:
2x+5=105
2x=100
2x/2=100/2
x=50
a cheetah can run 112km/h over a 100-m distance. what is this speed in meters per second
The modern atomic theory has been updated over the years as new observations of the atom have been made. What do these changes say about the strength of the modern atomic theory
Answer:
The answer is "It updates reinforce the idea, because it has been checked and modified several times, making it longer lasting".
Explanation:
The description of its empirical data throughout the world is a scientific principle. It's also based on facts and is often extensively tested by researchers. Repetitive done by scientists testing helps to enhance its body of knowledge. As just a result of advances in technology, after observation, data collection, and findings evaluation, scientific facts are checked, modified, and verified.
Which of the following most likely explains why the chemical symbol for calcium is Ca?
A. The symbol C was already used for carbon.
B. The symbol was assigned by modern alchemists.
C. Calcium is made of more than one type of atom.
Answer:
it is a latin word, so B
Explanation:
PLEASEE ANSWER FASST
The total number of protons and neutrons in an atom is its ___________________.
Answer:
nuggets
Explanation:
tazte very good
Answer:
It's atomic number is 2 so it has 2 protons. It's nucleus also contains 2 neutronns so 2+2=4 the answer is 4 in total.
Explanation:
I think. hehe I hope this helps though.
Which of the following did federalists oppose?
Answer:
The Federalists felt that this addition wasn't necessary, because they believed that the Constitution as it stood only limited the government not the people
A Potassium isotope contains 19 protons, 19 electrons and 21 neutrons. What is its mass number? 40
Answer:
17
Explanation:
you add 19+19 the subtract 21. I think
A potassium isotope contains 19 protons, 19 electrons, and 21 neutrons, so the mass number is 40 as the mass number of the atom is the sum of the protons and the neutrons, the mass number is 40.
What is the significance of the mass number in the atom?The mass number is significant as it is the sum of the number of protons and neutrons present in nucleus of an atom, which determines the atomic weight of an element and also determines its chemical properties and its position on the periodic table. Isotopes of an element have the same atomic number but a different mass number, so they have different properties than the original element.
Hence, a potassium isotope contains 19 protons, 19 electrons, and 21 neutrons, so the mass number is 40 as the mass number of the atom is the sum of the protons and the neutrons, the mass number is 40.
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What is the mass of a liquid having a
density of 1.40 g/mL and a volume of
3090 mL?
Answer:
It has a mass of 4.326 grams.
Explanation:
Define and give 3 examples of psychical properties
Answer:
A physical property is any property that is measurable, whose value describes a state of a physical system.
Explanation:
-color
-density
-volume
Matching
Match the word to the definition. Write the letter on the line.
6. Type Scientfic nquiry
А. This group shows the effect of the variable being tested
7. Type_ Hypothesis
В. This is the one variable that is changed
8. Type Control group
с. A welltested explanation for experimental results
9. Type Experimental group D. The many ways in which scientists study the natural world
10 Type Independent variable E A possible answer to a scientific question
11 Type Dependent variable F This describes an observed pattern in nature
12 Type Scientific theory G This group is left alone and not experimented on
Н This is the veriable that gets measured
13 Type Scientific law
Click to add speaker notes
Answer:
6. Scientific inquiry - D
7. Hypothesis - E
8. Control group - G
9. Experimental group - A
10. Independent variable - B
11. Dependent variable - H
12. Scientific theory - C
13. Scientific law - F
Explanation:
6. Scientific inquiry - D
Scientific inquiry is the study of the explanation for the natural world phenomenon and it requires many scientific steps.
7. Hypothesis - E
A hypothesis is a possible explanation for a phenomenon or problem. It is tested in order to see if true or not.
8. Control group - G
The control group in a scientific experiment is a group of subjects did not get the treatment and left alone.
9. Experimental group - A
The experimental group is another hand group of subjects that gets treatment and shows the effect of the variable being tested.
10. Independent variable - B
Independent variables change or manipulated during an experiment and cause a response from the dependent variable.
11. Dependent variable - H
The dependent variable is a variable that is dependent on independent variables and changes in the independent variable.
12. Scientific theory - C
A well-tested explanation for experimental results with the scientific process.
13. Scientific law - F
This describes an observed pattern in nature
A car travels 350 km in 7 hours. What is the average speed of the car (in km/hr)?
Answer:
50 km/hr
Explanation:
just divide the distance by the time (350/7)
Answer:
50 km/hr
Explanation:
Distance = 350 km
Time = 7 hours
Average Speed = ?
[tex]Average\:Speed = \frac{Distance}{Time} \\\\Average\: speed = \frac{350\:km}{7\:hr} \\\\A.V = 50\:km/hr[/tex]
In which Group do most of the elements have 8 valence electrons?
A. Transition metals
B. Alkaline earth metals
C. Halogens
D. Noble gases
Hail is an example of which type of phase change?
A) Sublimation
B) Evaporation
C) Condensation
D) Freezing
Answer:
D) freezing
Explanation:Because hail sounds like it is hard and hail comes down and it hurts because it is freezing.
The hail can be defined as the conversion of the water to the ice. Thus, hail is an example of freezing.
What is phase change?The phase can be defined as the state of the matter. With the change in the temperature and the pressure values, the state of the matter, or the phase changes.
The hail has been the solid precipitation of the rain water. With the lowering of the temperature to the critical pressure, the water converts to ice.
The conversion of water to ice has been termed as freezing, Thus, hail is an example of freezing. Hence, option D is correct.
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Use the drop-down menus to complete the statements.
The
transports water and nutrients throughout the plant.
The
v transports food throughout the plant.
HELPPPP A S A P!!
Answer:the xylem transports water and nutrients throughout the plant
the pholem transports food throughout the plant.
Explanation:mark brainliest cuz like i gave u the answer lol
Answer:
xylem and pholum
Explanation:i did it on edge hope its right :)
also sorry if i spelled it wrong i have never been the best at grammar
C. A paramecium is a single-celled organism that lives in ponds. It travels at a rate of 2,000 micrometers per second. What is the speed of the paramecium in meters per hour?
Answer:
7.2 meters per hour
Explanation:
It is given that,
The speed of a paramecium is 2,000 micrometers per second.
We need to find the speed of the paramecium in meters per hour.
We know that,
[tex]1\ \mu m=10^{-6}\ m[/tex]
and
1 hour = 3600 seconds
[tex]v=2000\ \dfrac{\mu m}{s}\\\\=2000\times \dfrac{10^{-6}\ m}{(\dfrac{1}{3600})\ s}\\\\=7.2\ \text{meters/hour}[/tex]
Hence, the speed of the paramecium is 7.2 meters per hour.
difference between compound and element
Answer:
An element is a material that consists of a single type of atom. Each atom type contains the same number of protons. Chemical bonds link elements together to form more complex molecules called compounds. A compound consists of two or more types of elements held together by covalent or ionic bonds.
Explanation:
I hope it helped you
How many penicillin molecules would you have if you had a total of 36 hydrogen atoms? What would be the total atomic mass?
Answer:
Explanation:
Molecular formula of penicillin = C₁₆ H₁₈ N₂ O₄S
No of hygrogen atoms = 36
No of molecules = 36 / 18 = 2
molecular weight = 334 amu
molecular weight of 2 molecules = 334 x 2 = 668 amu.
What is absolute zero? A) The temperature at which the particles of matter are at their lowest energy points. B) The temperature at which the particles of matter are at their highest energy points. C) Other _______________
Answer:
A) The temperature at which the particles of matter are at their lowest energy points.
Explanation:
Absolute temperature refers to the lowest possible temperature. At this state, no heat energy remains in the substance; the energy of the particles are at their lowest energy points.
Are all physical reactions reversible?
Which types of native organisms do feral hogs most likely compete with for food sources?
Answer:
Here...
Explanation:
The feral hogs are most likely to compete with Herbivore and Carnivor for food sources. Option C is correct.
Herbivore:It is a type of food habit or nature in which an animal only eats plant or plants derived products.
For example Deer, Cows, etc.
Carnivorous:It is a type of food habit or nature in which an animal only eats other animal or animal-derived food.
For example- Lion, tiger, etc.
Since, feral hogs are omnivores who can eat both small animals and plants,
Therefore, the feral hogs are most likely to compete with Herbivore and Carnivor for food sources.
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How should the baking of a pizza be categorized? A) as an exothermic process because the dough releases heat B) as an endothermic process because the dough releases heat C) as an exothermic process because the dough absorbs heat D) as an endothermic process because the dough absorbs heat
Answer:
D
Explanation:
as an endothermic process because the dough absorbs heat
The baking of a pizza be categorized as an endothermic process because the dough absorbs heat.
What is an Endothermic reaction?This is the type pf reaction in which heat is absorbed from the surroundings in a reaction.
During baking, the oven which is the surrounding is usually hot which brings about the dough absorbing the heat. This depicts an endothermic process and makes option D the most appropriate choice.
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What is the force of gravity acting on an object? (3 points)
Velocity
Mass
Weight
Pounds
the answer of these question is weight
Which of these is a property of a substance that is composed of atoms that are held together by metallic bonds?
It has a low melting point.
It can be flattened and bent.
It cannot be shaped into wires.
It does not conduct electricity.
Answer:
B: it can be flattened and bent
Explanation:
Metals are malleable and can be flattened. Metals are ductile and can be deformed and bent.
Metals are bonded together by metallic bonds.
Hence a substance that is composed of atoms that are held together by metallic bonds can be flattened and bent.
The property of a substance that is composed of atoms that are held together by metallic bonds is it can be flattened and bent
What is metallic bond ?Metals are malleable, ductile substance can be deformed when it is bent down, theses are bonded by metallic bond and can be flattened.
The metallic bond is a force of attraction which is responsible for holding the atoms together, releases electrons to achieve the configuration of a noble gas.
in this type of bonding all the atoms lose their electrons from their outermost layers that move more or less freely between them, forming an electronic cloud
The metallic bond is the exceptional bond where the electrons are not present exclusively between a pair of atoms, but these are relocated among millions of them called as "sea of electrons" by cohesive bond.
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(1 kilometer = 1,000 meters, 1 hour = 60 minutes, 1 minute = 60 seconds) Complete the steps necessary to convert 55 kilometers per hour to meters per second. Min 60 1,000 15.28 100 sec
Explanation:
55 kilometers per hour to meters per second
First we have to convert the kilometers to grams;
1 kilometer = 1,000 meters
This means we have;
55000 meters per hour
Converting hour to seconds;
1 hour = 60 minutes
1 minute = 60 seconds
1 hour = 60 * 60 = 3600 seconds
We divide 55000 by 3600;
55000 / 3600 = 15.28 meters per second
Explanation:
55 kilometers per hour to meters per second
First we have to convert the kilometers to grams;
1 kilometer = 1,000 meters
This means we have;
55000 meters per hour
Converting hour to seconds;
1 hour = 60 minutes
1 minute = 60 seconds
1 hour = 60 * 60 = 3600 seconds
We divide 55000 by 3600;
55000 / 3600 = 15.28 meters per second
What are five ways to identify a chemical reaction
Answer:
A chemical reaction occurs when a substance is rearranged to form a new substance. It is possible to identify if this has taken place from one of the five signs of chemical change. These changes include color change, temperature change, precipitate formation, gas production and light emission.
Explanation:
hope it helps :))
Answer:
A chemical reaction occurs when a substance is rearranged to form a new substance. It is possible to identify if this has taken place from one of the five signs of chemical change. These changes include color change, temperature change, precipitate formation, gas production and light emission.
hope it helps :)
measure the mass of 1 gram of sand
Answer:
Mass: 1 gram
Explanation:
This question doesn't make sense because the mass would be 1 gram.
Grams are a unit of mass.
The chemical symbol for silver oxide, an ionic compound used to make button batteries, is made of silver and
oxygen and has a chemical formula of Ag20.
Answer 2 and 1
Answer:
2 Silver Ions
1 Oxygen Ion
Explanation:
Edg2021
The chemical symbol for silver oxide is not Ag₂0. The correct chemical formula for silver oxide is Ag₂O.
Silver oxide (Ag₂O) is an ionic compound composed of silver ions (Ag⁺) and oxide ions (O₂⁻). It is commonly used in button batteries as a cathode material. In this compound, two silver ions combine with one oxide ion to form a stable structure.
The chemical formula Ag₂O indicates that there are two silver ions (Ag⁺) and one oxide ion (O₂⁻) in each formula unit of silver oxide. The subscript 2 after Ag indicates that there are two Ag⁺ ions present, while the absence of a subscript after O indicates that there is one O₂⁻ ion.
Hence, the chemical formulae are discussed above.
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What is the term for a ratio of equivalent measurements that can be used to change a value from one until into another
Answer:conversion factor
Explanation:
Terry bought a gold necklace at a pawnshop and was wondering if it was “real” gold. She decided to perform a density test. She placed the necklace in a graduated cylinder of water that had 47.00 mL of water and the water rose to 48.35 mL. She then weighed the necklace and found it to have a mass of 22.89 g. What is the density of Terry’s necklace?
Answer:
d = 16.96 g/mL
Explanation:
Given that,
Initial water level in graduated cylinder is 47 mL and final water level is 48.35 mL.
The weight of the neclace is 22.89 g.\
We need to find the volume of the necklace. We know that, density equals mass per unit volume. So,
[tex]d=\dfrac{m}{V_f-V_i}\\\\d=\dfrac{22.89\ g}{(48.35-47)\ mL}\\\\d=16.96\ g/mL[/tex]'
Hence, the density of Terry’s necklace is 16.96 g/mL.
Answer:
A
Explanation:
The new mine means the supply is high and the price is low, so she can afford the necklace