Answer:
[tex]a=64.7mg[/tex]
Explanation:
Hello,
In this case, we need to remember that for the required time for a radioactive nuclide as radium-226 to decrease to one half its initial amount we are talking about its half-life. Furthermore, the amount of remaining radioactive material as a function of the half-lives is computed as follows:
[tex]a=a_0(\frac{1}{2} )^{\frac{t}{t_{1/2}} }[/tex]
Therefore, for an initial amount of 100 mg with a half-life of 1590 years, after 1000 years, we have:
[tex]a=100mg(\frac{1}{2} )^{\frac{1000years}{1590years} }\\\\a=64.7mg[/tex]
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Answer:
Explanation:
reaction A is an acid base reaction
here MgO is base and H2SO4 is an acid
reaction B is an acid base reaction
here CO3^-² is weak base and H+ is an acid
reaction D is an acid base reaction water is amphoteric in nature here it behave like base and HCL is an acid
reaction F is acid base reaction
here NH3 is an base and HCL is an acid
reaction G is acid base reaction
here NaOH is base and HCL is an acid
in reaction c and e Al is hard acid and Cu is soft acid and HCL is acid and Zn is base but i m not confirmed that these reactions are acid base or not
If an atom has 16 protons, 14 neutrons, and 18 electrons. What is the charge of the nucleus?
Answer:
The charge of nucleus will be +2.
Explanation:
Given that,
Proton = 16
Neutron = 14
electron = 18
We know that,
Atomic number :
The number of proton in the nucleus is equal to the atomic number.
The number of protons is equal to the number of electrons for neutral atom.
So, the atomic number is same as the number of electrons.
Here, the number of electron is more than 2 of number of proton.
Hence, The charge of nucleus will be +2.
If A • B*2 = 1.8 x 10*-7, and C•B/D = 7.2 x 10*-4, find the value of A•D*2/C*2
Answer:
A*D²/C² = 0.347
Explanation:
A*B² = 1.8*10⁻⁷----- (1)
making A subject of formula; A = 1.8 * 10⁻⁷/B² ----(2)
C* B/D = 7.2*10⁻⁴ ----(3)
making C subject of formula; C = D * 7.2*10⁻⁴/B ----(4)
substituting the values of A and C in the equation A*D²/C²
A*D²/C² = (D² * 1.8 * 10⁻⁷/B²)/(D * 7.2*10⁻⁴/B)²
A*D²/C² = (D² * 1.8 * 10⁻⁷/B²)/(D² * 5.184*10⁻⁷/B²)
A*D²/C² = D² * 1.8 * 10⁻⁷/B² * B²/D² * 5.184*10⁻⁷
A*D²/C² = 1.8 * 10⁻⁷/5.184*10⁻⁷
A*D²/C² = 0.347
How are the steps you went through when discovering a new species similar to the steps of the scientific method? Were any steps skipped?
Answer:
Most steps were skipped they couldn't predict what it would be they couldn't really observe I font think they used very many.
what is 98.723 m= cm
Explanation:
To change from m to cm, divide by 100
[tex] \frac{98.723}{100} \\ = \: 0.98723cm[/tex]
A guy swam a 50 meter freestyle in 21.93 seconds. How fast is this in miles per hour?
Answer:
Speed = 5.107 mile/hrExplanation:
Given:distance =50m = 0.0311 mile
Time= 21.93 seconds/3600 =0.00609 hour
Speed=?
Speed= Distance / Time = 0.0311 / 0.00609 = 5.107 mile/hrQuestion 6
6. Ozone protects living organisms from damaging UVB rays.
True
False
Answer:
True
Explanation:
Ozone protects living organisms from damaging UVB rays
Answer:
A: True
Explanation:
The ozone layer acts as an invisible shield and protects us from harmful ultraviolet (UV) radiation from the sun.
The current day periodic table is organized by
Answer:
Dmitri Mendeleev
Explanation:
Dmitri Mendeleev published the first recognizable periodic table in 1869, developed mainly to illustrate periodic trends of the then-known elements. He also predicted some properties of unidentified elements that were expected to fill gaps within the table. Most of his forecasts proved to be correct
Answer:
Mendeleev periodic table
Explanation:
In 1869, just five years after John Newlands put forward his
Law of Octaves, a Russian chemist called Dmitri Mendeleev
published a periodic table. Mendeleev also arranged the
elements known at the time in order of relative atomic mass
Why is calcium chloride (rock salt, CaCl2) more effective than sodium chloride (table salt, NaCl) at de-icing roads in the winter? A. Calcium chloride only breaks into 2 ions, while sodium chloride does not break up and remains 1 ion. B. Calcium is a larger molecule than sodium, so it has a greater effect. C. The additional chlorine atom forms a stronger bond between the atoms in calcium chloride than in sodium chloride, so calcium chloride remains one molecule while sodium chloride breaks apart. D. Calcium chloride breaks into 3 ions, while sodium chloride only breaks into 2 ions.
Answer:
The correct option is;
D. Calcium chloride breaks into 3 ions, while sodium chloride only breaks into 2 ions
Explanation:
To help melt the ice on icy streets, calcium chloride (CaCl₂) is a more preferred salt type to sodium chloride (NaCl) as when it dissociates into ions in the ice, it forms three ions: a calcium ion, Ca²⁺, and two chloride ions, 2 Cl⁻, while sodium chloride forms two ions: one sodium ion, Na⁺, and one chloride ion, Cl⁻
According to the freezing point depression equation, we have;
ΔT = [tex]K_f[/tex] × m × i
Where;
ΔT = Change in freezing point temperature
[tex]K_f[/tex] = The freezing point depression constant
m = The solution's molality
i = van't Hoff factor
The calcium chloride salt will cause the most depression because the van't Hoff factor is 3 for calcium chloride and 2 for sodium chloride.
Answer:
d im pretty sure i got the same answer
Explanation:
what is five plus forty five
Answer:
5+ 45 = 50 is the answer....
Answer:
55. I hope this helps you!
A clock gains 0.020 seconds per minute. How many seconds will the clock gain in exactly 6 months, assuming exactly 30 days per month? (Chemistry)
Answer: 5184.000 seconds
Explanation:
If there are 30 days per month then we are trying to find how many seconds the clock will gain in 180 days (30*6). If the clock gains 0.020 seconds per minute, then it gains 28.800 seconds per day (0.020*60*24). We can then multiply this by 180 days to get 5184.000 seconds.
Why do our hair become grey?
Answer:
As humans, we have melanin in our hair but as we grow the pigment cells in our hair follicles gradually die. When there are fewer pigment cells in a hair follicle become a more transparent color. Our hair goes through its natural cycle of dying and regenerating, it’s more likely to grow in as gray after the age of 35. Stress can sometimes speed it up
Explanation:
Answer:
As we get older, the pigment cells in our hair follicles gradually die. When there are fewer pigment cells in a hair follicle, that strand of hair will no longer contain as much melanin and will become a more transparent color — like gray, silver, or white — as it grows.
The solubility of KNO3 is 32g/100g of water at 20oC and 62g/100g of water at 40oC. What will you observe if a saturated solution of KNO3 at 400C is cooled to 20oC.
Answer:
Explanation:
Solubility of KNO₃ at 20° C = 32 g / 100g of water
that means , per 100 g of water maximum of 32 g of KNO₃ can be dissolved at 20° C .
Solubility of KNO₃ at 40° C = 62 g / 100g of water
that means , per 100 g of water maximum of 62 g of KNO₃ can be dissolved
40° C.
So when a saturated solution in which maximum KNO₃ has been dissolved is cooled from 40° C to 20° C , due to decrease in solubility at lower temperature some KNO₃ will come out of the solution . Per 100 gram of saturated solution , 62 - 32 = 30 g of KNO₃ will precipitate out or come out of water . They can be filtered out .
consider three elements A B and C all of which have atomic numbers of less then 20. The atomic number of A is x, and the atomic number of B is three less than the atomic number of A
Element A forms cations with formula A+ and reacts with element C to form a solid substance with the formula AC
What is element A
Which group does element C belong to
Answer:
LiH
A is lithium
group 1 or 7
Is atomic mass and molar mass same?
Answer:
Atomic mass is the mass of an atom and is given in a.m.u. (atomic mass unit).
Explanation:
Atomic mass is the mass of an atom and is given in a.m.u. (atomic mass unit). However, a molar mass is the mass of one mole atoms or molecules and is given in grams. Sodium atom has a mass of 23 a.m.u. however, the molar mass of sodium is 23g/mol.
In stomach, Hydrochloric acid kills micro-organisms in the food. Stomach juices begin to break down p to amino acids. Stomach juices begin to break down p____________ to amino acids. please answerr <3333
[tex] \huge{ \underline{ \boxed{ \bf{ \green{Answer:}}}}}[/tex]
Inside the stomach, Hydrochloric acid kills micro-organisms in the food. Stomach juices begin to break down proteins to amino acids.
✤ So, Fill the blank with proteins.
Explanation:-Inside the stomach, the digestion of proteins starts due to the action of pepsin enzyme.But this enzyme remains inactive and is activated by the Hydrochloric acid(HCl).The Hydrochloric acid also helps in killing the germs and microbes which entered along with food.The mucous lines the wall of stomach to protect it from the harm caused by HCl because HCl is a strong acid.In stomach, The partial digestion of proteins occur and rest is digested in the small intestine by Trypsin(Pancreatic enzyme) and Intestinal juices.━━━━━━━━━━━━━━━━━━━━
Round your answer to the correct number of significant figures or decimal places: 0.005-0.0007=
Answer:
0.0043
0.004 if to one significant figure
0 to one decimal place.
A sample of iron has the dimensions of 2 cm x 3 cm x 2 cm. If the mass of this
rectangular-shaped object is 94 g, what is the density of iron?
Answer: Volume iron = 2 x 3 x 2 => 12 cm³
Mass = 94 g
D = m / V
D = 94 / 12
D = 7.833 g/cm³
Explanation:
*
6. "The mixture is green in color." This confirms that the mixture is a
The question is incomplete, so the complete question is as follows:
"The mixture is green in color.” This confirms that the mixture is a.
A) suspension B) solution C) colloid D) this proves nothing
Answer:
D) this proves nothing
Explanation:
The green-colored mixture does not prove anything about the mixture because only the color of mixture can not decide the typw of mixture.
Several other properties affecting the type of mixture are the size of particles and also dispersion of particles in the solution.
Hence, the correct answer is "D",
Balance the following equations: i) KClO3 KCl + O2 ii) HNO3 + NaHCO3 NaNO3 + H2O + CO2 iii) Na + H2O NaOH + H2
i) 2KClO3 → 2KCL + 3O2
ii) HNO3 + NaHCO3 → H20 + CO2
iii) 2Na + 2H2O → 2NaOH + H2
chloride gas is usually collected by downward delivery after preparation because chlorine gas is
A. soluble in water
B. denser than water
c. less dense than air
d. very reactive
is solar energy ecosystem services if so why
yes
Explanation
it is using the sun energy as an energy resource and is therefore Eco friendly
Hope this answer correct :)
please help me with this!
Answer:
4.76 × 10¯⁵ cm
Explanation:
The conversion of 476 nm to cm can be obtained as follow:
1. Conversion of 476 nm to m
Recall
1 nm = 1 × 10¯⁹ m
Therefore,
476 nm = 476 × 1 × 10¯⁹ = 476 × 10¯⁹ m
2. Conversion of 476 × 10¯⁹ m to cm
Recall:
1 m = 100 cm
Therefore,
476 × 10¯⁹ m = 476 × 10¯⁹ × 100
476 × 10¯⁹ m = 476 × 10¯⁷ cm
476 × 10¯⁹ m = 4.76 × 10¯⁵ cm
Therefore,
476 nm is equivalent to the 4.76 × 10¯⁵ cm
Which statement correctly describes a scientific theory? A. It is accepted as true indefinitely. B. It is based on repeated investigations. C. It is equivalent to a scientific law. D. It is accepted as false.
how does getting funding from the government affect scientific research?? a- the government helps the scientist decide what research is important b- the government tells the scientist what research they can do c-scientist can only do research that helps the government protect its citizens d- scientist have to follow government rules made to protect people
Answer:
d- Scientists have to follow government rules made to protect people.
Explanation:
Scientific research fosters our understanding of the world around us. It helps people to learn to promote critical thought and problem-solving. Although there may not be an immediate practical use of the research, in the long term the study could benefit humanity. Scientific research is the product of creative ideas and collaborative communication that the proper role of government is often restricted to funding the research. The role of the government is to perform its reasonable and valid duties of defending human rights and enhancing the independence of the human.
Answer:D
Explanation:
A scientist wants to find the percent of teens that like the taste of "brand X" lemonade over "brand Y" lemonade. She conducts a taste test of 500 teenagers. She gives each teen a bottle of lemonade with the labels showing the brand of each lemonade. She asks each teenager to taste each brand after drinking water in between. She finds that 50% of teens like brand X and 50% like brand Y lemonade. Why are the results of the survey most likely unreliable?
Answer:
She gave them bottles with labels showing the brands
Explanation:
the teens could have been biased due to knowing the brand. It would have been more reliable if the label was covered or removed.
6. Two unknown compounds are tested. Compound I contains 15.0 g of hydrogen and 120.0 g of oxygen. Compound II contains 2.0 g of hydrogen and 32.0 g of oxygen. Are the compounds the same?
Answer:they are not the same because the composition differ
Explanation:
Which of the following is displaced by 'Cu'? 1.Fe2+ 2.Ag+ 3.Zn2+ 4.Al3+
Answer:
2.Ag+Explanation:
This problem tests our knowledge/understanding of the electro-chemical series.
Electrochemical series or activity series is a list that describes the arrangement of elements in order of their increasing electrode potential values.
In the electro-chemical series metals placed above can displace metals below from their salt solutions.
In this question given the series as stated
1. Fe2+
2.Ag+
3.Zn2+
4.Al3+
In the series we have metals stated as Zn>Fe>Cu>Ag.
Cu will displace silver Ag+ because it is below it in the series
Introduction of transition metals? (one big paragraph please)
Answer:
its answer this question q1
Identify the terms described by selecting the correct word from the drop-down menu.
Anything that has mass and takes up space
The part of Earth in which life exists, including land, water, and air
Answer: Matter
Biosphere
Explanation:
The substance that occupies space and mass is called matter, and the biosphere is the part of the earth that includes life. Thus, the correct options are 1. c and 2. b.
What is the matter?A matter has been defined as a substance that is made of atoms and has a mass that results in it occupying some space. The matter can be in the form of liquid, solids, or gas. The matter is present everywhere and can be interconnected. Thus, 1. c is correct.
The biosphere is defined as the sphere that combinedly comprises the hydrosphere, lithosphere, and atmosphere and is the part where life exists on the earth. It includes the elements air, water, land, etc., and all the ecosystems that range from oceans to mountains. Thus, 2. b is correct.
Therefore, options 1. c. matter and 2. b. the biosphere is correct.
Learn more about the matter, here:
https://brainly.com/question/9402776
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Your question is incomplete, but most probably your full question was,
1. Anything that has mass and takes up space
AtomElementMatter2. The part of the earth in which life exists including land water and air
ThermosphereBiosphereExosphere