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An experiment performed to determine the density of lead yields a value of 10.95 g/cm3. The accepted value for the density of lead is 11.342 g/cm3. Find the percent error.
Answer:
3.45618%
Explanation:
Percent Error = measured value - accepted value/ accepted value x 100
Measured Value: 10.95
Accepted Value: 11.342
Work:
[tex]\frac{10.95-11.342}{11.342} *100[/tex]
[tex]\frac{-0.392}{11.342} *100[/tex] = -3.45618
You cannot have a negative percentage. Therefore the answer is 3.45618%
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:
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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Please Help!!! Time LImit. Extra Points and Brainiest.
Acids are a group of molecules with similar physical and chemical properties. Acids react with metal, but vegetable oil does not. What can you infer from this observation? Choose the two statements that apply.
A. The combination of atoms in acids and oil result in very different properties.
B. Acids and oil have different properties because they have different shapes.
C. The atoms present in molecules affect their properties.
D. Vegetable oil is most likely some type of acid.
Answer:
A and D
Explanation:
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.
A balloon has a volume of 10,500 liters, and the temperature is 15°C. If the temperature were -25°C, what would the volume of the balloon be?
12,194 L
9,042 L
Answer: 12,194 L
Explanation:
WILL MARK BRAINLIEST
7. When the numbers 5.56 x 10^2 and 3.81 x 10^3 are added the result is:
a) 4.36 x 10^3
b) 4.366 x 10^3
c) 4.366 x 10^2
d) 4.37 x 10^3
Answer:
option b
Explanation:
556+3810
=4366
=4.366*10^3
Hope it helps
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Greg ran for 25 minutes at a speed of 5 km/m. Find the distance.
Here it is⬆️ Distance is 125 km
How many neutrons in beryllium
Answer:
There are 5 neutrons in beryllium
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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plz tell me I will also give brainiest. forces can be ________ or unbalanced
Answer:
balanced
Explanation:
hope this helps
Answer:
[tex] \boxed{ \bold{ \huge{ \boxed{ \sf{ \: Balanced}}}}}[/tex]
Explanation:
Forces can be balanced or unbalanced.
[tex] \bigstar {\sf{ \: \: Balanced \: force}}[/tex]
When a number of forces acting on a body do not change its state of rest or uniform motion in a straight line , the forces are said to be balanced forces. For example : In the game of tug of war, two teams pull a rope in opposite directions. When the two teams exert equal and opposite forces on the rope, the rope remains steady and does not move in any direction. It appears as if no force is acting on the rope. Thus, the two forces acting on the rope in this case are balanced forces.
[tex] \bigstar{ \sf{ \: Unbalanced \: force}}[/tex]
When a number of forces acting on a body change it's state of rest or uniform motion in a straight line, the forces are said to be unbalanced forces. For example, if we push a toy car towards east, it moves towards east. If it is pushed towards west, it moves towards west. This unbalanced force produces motion.
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What’s the independent variable, dependent variable, experimental variable and constant?Scenario #1: Traci thinks that instrumental music played in the office will increase the productivity
of workers at the office. She creates two groups of 50 workers each and assigns each group the
same task in this case, they are asked to staple a set of papers). Group A has instrumental music
playing while they work. Group B does not have any music playing for them. After an hour, Traci
counts how many stacks of papers each group has made. Group A made 2,113 stacks. Group B
made 1,587 stacks.
Answer:
independent variable- instrumental music
dependent variable- Number of stacks of papers made
experimental variable- Group A has instrumental music
playing
constant- same task,
Explanation:
The ground-state electron configuration for an element contains an unpaired 3s electron.
Answer:
Na
Sodium is located in the third row of the periodic table, where the 3s3s3, s orbital is being filled. Because sodium is the first of the two 3s3s3, s elements, its ground-state electron configuration contains a single, unpaired 3s3s3, s electron.
Explanation:
its late but ik someone can use it
The ground-state electron configuration for an element contains an unpaired 3s electron is Sodium, Na.
The ground state electron configuration of an element shows a series of how its electrons are arranged in thier orbitals at their lowest energy state.
The element which contained an unpaired 3s electron is the Alkali metal, Sodium.
Sodium, Na has atomic number of 11 and at ground state and will therefore be written as 1s²2s²2p⁶3s¹ We can also write the condensed form since the core electrons is the same with Ne, a noble gas which is [Ne]3s1.
The s orbital should contain at most 2 electrons , since for sodium, it has 1 electron in the 3s orbital, we say it is unpaired.
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There are 5 areas of chemistry:physical chemistry, organic chemistry, analytical chemistry, biochemistry and inorganic chemistry.identify which of the five area of chemistry best fits the action done by zoe, a chemist. zoe is using an instrument called a spectrophotometer to precisely determine the levels of various chemicals in a sample of drinking water.
If someone could help me I would really appreciate it. Thank you!
Answer:
Analytical chemistry
Explanation:
because in analytical chemistry checks that different chemicals in water,salt etc....
saftey goggles are worn in the lab-
Answer:
Yes
Explanation:
Is this a question or what?
Answer:
this is true and should always be true
Explanation:
if they are not on in the lab you or others may get injured
How do atoms emit light ?
Answer:
The frequencies of light that an atom can emit are dependent on states the electrons can be in. When excited, an electron moves to a higher energy level or orbital. When the electron falls back to its ground level the light is emitted.
A marathon is approximately 42.195 km Convert the distance to
centimeters.
Answer:
4219500 centimeters
Explanation:
I hope this helped!
Which would be an example of a homogeneous mixture?
Question 10 options:
Sprite
marinara sauce
air
ranch dressing
Answer:
Air
Explanation:
Air is an homogeneous mixture because it contain gaseous samples that have the same proportion throughout it's given sample. Air is a mixture of gaseous substances of 78.09% nitrogen, 20.95% oxygen, 0.93% argon, 0.04% carbon dioxide, 1% of water vapor and small amounts of other gases in same proportion.
How many joules of heat are needed to raise the temperature of 10.0 g of aluminum from 22°C to 55°C, if the specific heat of aluminum is 0.90 J/g°C?
Answer:
0.90 degree C
Explanation:
The key to this problem lies with aluminium's specific heat, which as you know tells you how much heat is needed in order to increase the temperature of 1 g of a given substance by 1∘C
In your case, aluminium is said to have a specific heat of
0.90 J g∘ C.
A graduated cylinder is placed on an electronic balance, and the scale reads 78.32 g. 10.0mL of glycerine are added, and the scale reads 91.78 g. What is the density of glycerine
Answer:
1.346 g/mL
Explanation:
The density is defined as the mass of a substance per unit of volume.
In the problem, you add 10.0mL of glycerine. the mass change from 78.32g to 91.78g. The difference is the mass of the glycerine:
Mass glycerine: 91.78g - 78.32g = 13.46g
As the volume added was 10.0mL, the density, δ, in g/mL is:
δ =13.46g / 10.0mL =
1.346 g/mL
What type of element is used in the electronics industry because it is a semiconductor
Answer:
Pure Silicon in Electronics
Silicon material is commonly used as a semiconductor in electronics: devices such as transistors, printed circuit boards, and integrated circuits make use of silicon's highly conductive properties to maximize their performance.
Explanation:
How do you know when a boy likes you? A. He talks to you a lot B. He is mean to you C. He hugs you a lot D. He tries to take your stuff from you
Answer:
I feel it would be C or D but more likely to be D
Explanation:
Answer:
I guess it is A he talks to u alot but boys are different so it could be each one u know?
18 grams
4 kilograms
8 kilograms
Answer:
1 18 grams
2 500g
4 960 grams
5 7 kilograms
Please please help :(
Answer: ¹²₅C
Explanation:
¹²₅C is incorrect. The superscript is the atomic mass. This varies between each element. The subscript is the atomic number. This doesn't change. You will see every element has the correct atomic atomic number except for Carbon. Carbon should have atomic number 6.
A
is a changeable factor in an experiment.
O THEORY
O LAW
O HYPOTHESIS
O CONTROL
O VARIABLE
Answer:
Variable is a changebale factor in an experiment.
Explanation:
Answer: O VARIABLE
Explanation:
Is the equation above balanced or unbalanced? Explain? Worth 55 points.
Answer:
For me, it is balanced
Explanation:
Because the amount of element Zn reaction is equal the production. Also as the amount of Hydrogen and Chloride in the reaction and the production are equal.
+
equations
2. Na,CO3(aq) + 2K(s) → K2CO3(aq) + 2Na(s)
Answer:
Explanation:
Na2CO3(ag) +2k(s) →K2CO3 (aq) + 2Na(s)
2) A wooden block has a volume of 176 cm3 and a density of 18.2 g/ cm3. What is the mass?
Answer:
9.67 g
Explanation:
176 cm³ / 18.2 g/cm³ = 9.6703296703...
I rounded to the nearest hundredth
- 1. Justin usually blows his nose using Kleenex tissues. His snot keeps leaking through the tissue. He decided he is going to create an experiment to find out if there is something better. What is his dependent variable? - A. Justin - B. Amount of snot the tissue can hold - C. Amount of tissue - D. Type of tissue
Answer:
B. Amount of snot the tissue can hold
Explanation:
In this specific scenario, the dependent variable would be the amount of snot the tissue can hold. That is because this is what Justin is trying to measure, which is also dependent on the type of tissue which would be the independent variable in this scenario. The different types of tissues can absorb different amounts of snot and this is what Justin ultimately wants to determine.
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.