The first record of the scientific method being used was approximately
O A) 600 years ago.
O B) 3,000 years ago.
O C) 50 years ago.
O D) 1.200 years ago.
Answer:
600 years ago
Explanation:
it was first recorded by England's Sir Francis Bacon (1561-1626)
A scientist observes that the electric resistance of a superconducting material drops to zero when the material is cooled to very low temperatures which of the following statements best describe what the scientist is observing
Answer: The scientist is observing an intensive property of a superconductor. ( So C)
Explanation: edu
Answer: the scientist is observing an intensive property of a superconductor.
How do you know if a energy level is full
Answer:
By checking Level.ok!!
What is the percentage by mass of a solution with 30.0g salt dissolved in water to make 650.0g 0f solution?
Please help
Answer:
The percentage by mass of a solution with 30.0g salt dissolved in water to make 650.0g 0f solution is 4.61 %
Explanation:
The mass percentage of a solution is a measure of concentration that indicates the number of grams of solute that there are per 100 grams of solution.
The percent by mass is calculated as the mass of a component divided by the total mass of the mixture, multiplied by 100 to give a percentage.
[tex]percentage by mass=\frac{solute mass}{solution mass} *100[/tex]
In this case:
solute mass: 30 gsolution mass: 650 gReplacing in the definition of percent by mass:
[tex]percentage by mass=\frac{30 g}{650 g} *100[/tex]
Solving:
percent by mass= 4.61 %
The percentage by mass of a solution with 30.0g salt dissolved in water to make 650.0g 0f solution is 4.61 %
How many neutrons in beryllium
Answer:
There are 5 neutrons in beryllium
does anyone know the answeres
A hydrogen electron is elevated from level 1 to level 2. Another electron is elevated from level 2 to level 4. The transition requiring the greatest energy change is
Answer:
the answer is level 2 to level 4
Explanation:
hi I'm new here and here to help
Answer: Welcome to Brainly!
We are happy to have you! :)
The head of a pin is 1.5 × 10-3 m in diameter. If 1.136 × 107 atoms of oxygen can fit across the head of a pin, what is the atomic radius of oxygen?
About five million million hydrogen atoms could fit. Some factors would affect that number like the area of the head and the size of atoms (as well as attractions between atoms). Some atoms are larger than others.
If 1.136 × 10⁷ atoms of oxygen can fit across the head of a pin whose diameter is 1.5 × 10⁻³ m, the atomic radius of oxygen would be 6.60 × 10⁻¹¹ m.
The head of a pin is 1.5 × 10⁻³ m in diameter. If 1.136 × 10⁷ atoms of oxygen can fit across the head of a pin, the diameter of each oxygen atom would be:
[tex]\frac{1.5 \times 10^{-3}m }{1.136 \times 10^{7}atom} = 1.32 \times 10^{-10}m/atom[/tex]
The atomic radius of oxygen would be half of its diameter.
[tex]\frac{1.32 \times 10^{-10} m}{2} = 6.60 \times 10^{-11} m[/tex]
If 1.136 × 10⁷ atoms of oxygen can fit across the head of a pin whose diameter is 1.5 × 10⁻³ m, the atomic radius of oxygen would be 6.60 × 10⁻¹¹ m.
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What role does science play in changes?
Answer:
Science, as well as technological and metaphysical questions, should offer solutions to our everyday problems. The consistency of responses offered to society should be increased by research. Science, however, still needs to interact with society in conversation.
Explanation:
When an atom of a Radioactive element emits alpha radiation, an atom of a different element is formed. A different element is formed because the radioactive element has lost...
Explanation:
its its originality as an atom has to be pure
A different element is formed because the radioactive element has lost its originality as a pure atom when a radioactive element emits alpha radiation.
What is a radioactive element?Some elements of unstable atomic nuclei undergo radioactive decay to form stable nuclei because of the presence of excess nuclear charge inside them are known as radioactive elements.
The stability of nuclei of an element can be estimated by neutron to proton ratio. The atomic number up to Z= 20 is stable nuclei and contains an equal number of protons and neutrons. As the atomic number starts to increase, the repulsion forces between protons increase.
Thus, the neutron-to-proton ratios of stable nuclei increase with increasing atomic numbers. If elements with the atomic number, Z > 83 and n/p > 1.5 and they will be most unstable and radioactive.
For example, Pu-240 emits an alpha particle and gets converted into U-236 which is completely different from the original nuclei.
²⁴⁰Pu₉₄ → ⁴He₂ + ²³⁶U₉₂
Therefore, the radioactive element lost its identity after disintegration.
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How much copper is in 3.79 g of copper
Answer:
3.79 g
Explanation:
The sum of two integers is -4. Can the two integers both be positive?
Answer: No.
Explanation: A negative integer can only be made with 2 negative integers or 1 positive and 1 negative integer.
HELP 100 POINTS explain how you would separate the components of a dirty water mixture that consists of: • coffee grounds • garlic powder • vegetable oil • sodium chloride (table salt) • gravel and sand • water. For each step discuss what separation method you are using and why you chose that method
Note that all detail explanation on why or how will be attached at the end
Step 1: Removing the Oil
Theoretically, step 1 and 2 can be alternated and preferably I would start with step 2, but I thought of one first. I would begin by setting up the liquid mixture in a funnel with a closed twist valve. Once the water mixture and oil has separated, I would slowly remove all the water, leaving the oil.
Step 2: Removing the Gravel and Sand
The second step is to filter out solids by using a sand filter. This filter is made by using a Styrofoam cup that has had small holes punched into the bottom with an open paperclip. The cup is filled with layers of clean washed gravel. The gravel will be layered by putting course gravel in the bottom and fine sand in the middle followed by course sand on the top. The gravel on the bottom stops the loss of sand out of the holes and the gravel on top stops the sand from washing out as a sample is poured.
Step 3: Removing the Coffee Grounds and Garlic Powder
You would start by lining a clean funnel with a coffee filter or something comparable. Then, you would add a spoonful or so of Charcoal to the funnel. Then you would pour the mixture of water, garlic powder, salt and coffee grounds into it.
Step 4: Removing Salt
You would preform a simple evaporation to remove the salt from the water. If the water is still needed, then you can preform a sealed distillation which has the same effect, but just keeps the water.
Step 5: Celebrate!
If you are doing this is a school, congratulations! you just finished your assignment/lab! If you are doing this in the wilderness for survival, congratulations! you won't die so soon!*
*The purification of water will not guarantee your extended survival in the wilderness, just extend the time in which you will not die of dehydration.™
Explanation:
Step 1 works because the density of oil and water are different, so as you let the liquid settle, the two liquids will separate into two sections. This allows you to funnel the water out. Step 2 work because the gravel and sand you want out cannot pass the sand-gravel filter you made (as long as it was made correctly) Step 3 works because the garlic powder and coffee grounds cannot pass the filter and the smell and colour that leaked into the water would be removed by the charcoal. Step 4 works because as water evaporates or is boiled off, the salt cannot evaporate with it, so it is left behind. Like how I was in the mall. Step 5 works because this was a long explanation and now you can go look at memes.
Read the claim.
Breakfast is an important meal. It jump starts the body’s process of using calories to break down food. Appetite can decrease with age, but going too long without eating causes metabolism to slow down. Current research shows that incorporating legumes such as lentils and chickpeas into meals boosts metabolism for twenty-four hours. Who might benefit from this claim?
A.people who have a fast metabolism
B.stores that sell exercise equipment
C.people who take vitamin supplements
D.grocery stores that sell legumes
Does Kumiho the legendary exist??
Answer: Deriving from ancient Chinese myths and folklores, a fox that lives a thousand years turns into a kumiho, like its Japanese and Chinese counterparts. It can freely transform, among other things, into a beautiful woman often set out to seduce boys, and eat their liver or heart (depending on the legend).
Hoped that helped!
Answer:
No
Explanation:
The Kumiho is similar to other fox creatures, such as the Japanese kitsune and Chinese Huli jing. Even though they have similar magical abilities and longevity, Kumiho is more malevolent than other fox spirits. Of these long-lived legendary creatures, the Kumiho is the only fox that kills and eats humans. Kumiho is just a myth itś not real and no one has seen this fox so "it" does not exist.
A sample of seawater weighs 250 g and has a volume of 173 ml. What is the density of seawater?
Answer:
The answer is 1.45 g/mLExplanation:
The density of a substance can be found by using the formula
[tex]density = \frac{mass}{volume} \\ [/tex]
From the question
mass of seawater = 250 g
volume = 173 mL
It's density is
[tex]density = \frac{250}{173} \\ = 1.4450867052...[/tex]
We have the final answer as
1.45 g/mLHope this helps you
What is the Thermal Energy?
Answer:
Thermal Energy is a certain type of energy that Heats.
Explanation:
"Thermal" is derived from "Thermo" which means heat.
why do atoms combine
Explanation:
Atoms form chemical bonds with other atoms when there's an electrostatic attraction between them. This attraction results from the properties and characteristics of the atoms' outermost electrons, which are known as valence electrons.
Boron (B) has two Isotopes, boron-10 and boron-11. The atomic weight of boron is the
A. combined masses of boron-10 and boron-11
B. average number of neutrons in boron-10 and boron-11
C. weighted average of the masses of boron-10 and boron-11
D. mass of boron-10 minus the mass of boron-11
Answer:
C. is the correct answer
Explanation:
I just completed this question and got it correct.
Discuss the sources and harmful effects of the following air pollutants.(i) Carbon monoxide (ii) Sulphur dioxide (iii) Oxides of nitrogen
Answer:
Oxides of Nitrogen (NOx)
NOx is a collective term used to refer to two species of oxides of nitrogen: nitric oxide (NO) and nitrogen dioxide (NO2).
Annual mean concentrations of NO2 in urban areas are generally in the range 10-45 ppb (20-90 µgm-3). Levels vary significantly throughout the day, with peaks generally occurring twice daily as a consequence of "rush hour" traffic. Maximum daily and one hourly means can be as high as 200 ppb (400 µgm-3) and 600 ppb (1200 µgm-3) respectively.
Globally, quantities of nitrogen oxides produced naturally (by bacterial and volcanic action and lightning) far outweigh anthropogenic (man-made) emissions. Anthropogenic emissions are mainly due to fossil fuel combustion from both stationary sources, i.e. power generation (21%), and mobile sources, i.e. transport (44%). Other atmospheric contributions come from non-combustion processes, for example nitric acid manufacture, welding processes and the use of explosives.
Sulphur Dioxide (SO2)
SO2 is a colourless gas. It reacts on the surface of a variety of airborne solid particles, is soluble in water and can be oxidised within airborne water droplets.
Annual mean concentrations in most major UK cities are now well below 35 ppb (100 µgm-3) with typical mean values in the range of 5-20 ppb (15-50 µgm-3). Hourly peak values can be 400-750 ppb (1000-2000 µgm-3) on infrequent occasions. Natural background levels are about 2 ppb (5 µgm-3).
The most important sources of SO2 are fossil fuel combustion, smelting, manufacture of sulphuric acid, conversion of wood pulp to paper, incineration of refuse and production of elemental sulphur. Coal burning is the single largest man-made source of SO2 accounting for about 50% of annual global emissions, with oil burning accounting for a further 25-30%.
Carbon Monoxide (CO)
Carbon Monoxide is a colourless, odourless, tasteless gas that is slightly lighter than air.
Natural background levels of CO fall in the range of 10-200 ppb. Levels in urban areas are highly variable, depending upon weather conditions and traffic density. 8-hour mean values are generally less than 10 ppm (12 mgm-3) but have been known to be as high as 500 ppm (600 mgm-3).
CO is an intermediate product through which all carbon species must pass when combusted in oxygen (O2). In the presence of an adequate supply of O2 most CO produced during combustion is immediately oxidised to carbon dioxide (CO2). However, this is not the case in spark ignition engines, especially under idling and deceleration conditions. Thus, the major source of atmospheric CO is the spark ignition combustion engine. Smaller contributions come from processes involving the combustion of organic matter, for example in power stations and waste incineration.
Ozone (O3)
O3 is the tri-atomic form of molecular oxygen. It is a strong oxidising agent, and hence highly reactive.
Background levels of O3 in Europe are usually less than 15 ppb but can be as 100 ppb during summer time photochemical smog episodes. In the UK ozone occurs in higher concentrations during summer than winter, in the south rather than the north and in rural rather than urban areas.
Most O3 in the troposphere (lower atmosphere) is formed indirectly by the action of sunlight on nitrogen dioxide - there are no direct emissions of O3 to the atmosphere. About 10 - 15% of tropospheric O3 is transported from the stratosphere where it is formed by the action of ultraviolet (UV) radiation on O2. In addition to O3, photochemical reactions involving sunlight produce a number of oxidants including peroxyacetyl nitrate (PAN), nitric acid and hydrogen peroxide, as well as secondary aldehydes, formic acid, fine particulates and an array of short lived radicals. As a result of the various reactions that take place, O3 tends to build up downwind of urban centres where most of NOx is emitted from vehicles.
Explanation:
How many electrons does maganese 55 have?
Answer:
Maganese 55 has 25 electrons.
Hope this helps you!
Explanation:
Which form of heat transfer is the sun heating Earth's atmosphere? *
Answer:
Radiation
Explanation:
Radiation is the transfer of heat energy through space by electromagnetic radiation. Most of the electromagnetic radiation that comes to the earth from the sun is invisible.
Which can be categorized as a use of plasma in technology?
A. taking pictures of solar flares
B. observing the aurora borealis
C. making fluorescent lights for houses
D. making telescopes to observe distant stars
The answer would be: Making fluorescent light for houses.
Making fluorescent lights for houses can be categorized as use of plasma in technology.
What is Plasma Technology ?Plasma technology is commonly used in many industries, including in the automotive, microelectronics, packaging and medical device industries. Along with solid, liquid and gas, plasma is a state of matter.
State changes occur by either adding or removing energy from a substance.
Making fluorescent lights for houses can be categorized as use of plasma in technology
The mercury atoms in the plasma generate light very efficiently, but much of it is ultra-violet (UV), invisible to the eye and harmful to it (or rather, it would be, were it not absorbed by the glass).
The solution is to coat the inside of the tube with a glow-in-the-dark (fluorescent) paint, which absorbs the UV and re-emits its energy as visible light.
Therefore Option C is the correct answer.
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What is the most abundant greenhouse gas released through human activities? a. methane b. nitrous oxide c. carbon dioxide d. sulfur dioxide
Answer:
C. Carbon dioxide. (C02.)
Explanation:
Hope this helps. :)
Answer:
Carbon dioxide
Explanation:
Draw the Lewis dot diagram for a Mg- anion.
Answer:
..
Explanation:
Convert the following masses into kilograms:
(a) 2,300,000 grams
(b) 5,000 milligrams
(c) 23,000 micrograms
(d) 0.155 megagrams
Answer:
(a): 2,300 kilograms
(b): 0.005 kilograms
(c): 2.3 × 10^-5 kilograms
(d): 155 kilograms
Explanation:
Formulas:
(a); divide the mass value by 1000
(b); divide the mass value by 1e+6
(c); divide the mass value by 1e+9
(d); multiply the mass value by 1000
Chuck wants to know how many electrons in an atom are not paired up. Which model would be best for Chuck to write
out?
a set of quantum numbers for the last electron in the atom
a configuration with numbers letters and subscripts
a dot structure of the atom
an orbital notation of the atom
Answer:
D. an orbital notation of the atom
Explanation:
i took the test
Which sentence correctly uses parallel structure? The boss wants to know who can take the late shift tonight, open tomorrow morning, and who can work on the holiday. The boss wants to know who wants the late shift tonight, who can open tomorrow morning, and if you will work on the holiday. The boss wants to know who can take the late shift tonight, who can open tomorrow morning, and who can work on the holiday. The boss wants to know who can take the late shift tonight, who can open tomorrow morning, and which of us wants to work on the holiday.
Answer:
C) The boss wants to know who can take the late shift tonight, who can open tomorrow morning, and who can work on the holiday.
Explanation:
The sentence that has been in the parallel structure has been the boss wants to know who can take the late shift tonight, who can open tomorrow morning, and who can work on the holiday has been in parallel structure. Thus, option C is correct.
The parallel structure can be defined as the continuous repetition of the grammatical form in the sentence. The parallel structure has been able to provide equal importance to the tasks in the sentence.
In the given sentence, the varying task has been late shifts, open tomorrow, and work on holidays. The grammatical form of who can has been able to give equal importance to every task with the repetition.
Thus, boss wants to know who can take the late shift tonight, who can open tomorrow morning, and who can work on the holiday has been in parallel structure. Thus, option C is correct.
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Which of the following best specifies the purpose of error bars on a graph? To show the mean of a data set. To identify the independent variable. To give a visual display of measurement precision. To indicate the total number of measurements that are made.
Answer:
c
Explanation:
To give a visual display of measurement precision best specifies the purpose of error bars on a graph.
What are errors?Errors in chemical analysis result when there is a difference between observed value and the true value.If the magnitude of errors is large , it results in decrease in accuracy, reproducibility, and precision.
There are three types of errors:1) random error 2) systematic error 3) human error.The cause of random errors are difficult to quantify while the human errors can be minimized by taking a range of readings to reduce the error.
Errors while measuring boiling point may be human errors while noting down the boiling temperature or instrumental or systematic error if there is a fault in the thermometer.The experiments must be done with utmost care to minimize the range of errors.
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