what are stop signs from barack Obama?
Answer:
President Obama signs the Stop Trading on Congressional Knowledge Act in a ceremony at the White House. President Barack Obama delivers remarks prior to signing the STOCK Act in the South Court Auditorium at the Eisenhower Executive Building (EEOB) of the... sorry I have to hurryy
Explanation:
Volume = 90g / 3g cm3 What is the volume help ASAP
Answer:
The answer will be this 30g/cm3
what is second explain it briefly
Explanation:
it is that when an object is moving 25 m per sec to calculate its time we can simply divide 1.5 by 25 and multiply by 1
URGENT PLEASE ELPP!!!Calculate the density of a piece of metal that has a mass of 2.5 × 102 kg and a volume of 4.1 × 103 m3.
Answer:
Density =mass/Volume
First of all let's find the mass
= 2.5 ×102kg
= 225kg
Then the volume
=4.1 × 103 m3
=422.3m3
225kg /422.3m3
=0.53279659
The density of a piece of metal that has a mass of 2.5 × 102 kg and a volume of 4.1 × 103 m3 will be 6.03 kg/m³ .
What do you mean by the density of a substance ?
Density is defined as the ratio of mass of the object to the volume of the object. Different substances have different densities.
The mathematical expression for density is as follows:
Density=Mass/Volume
The mass of a substance is expressed in kilograms and the volume is expressed in liter.
Thus, the unit of density is kg L⁻¹.
The density of a substance does not depend on the amount of the matter.
Thus, density is an intensive property.
To calculate the density -:
Given,
Mass= 2.5 ×102 kg=2550 kg
Volume=4.1 × 103 m³=422.3m³
Density=mass/volume
Density=2550/422.3
Density=6.03kg/m³
Hence, 6.03kg/m³ is the density of a piece of metal .
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How nephthalene can be purified by sublimation
Answer:
sublimation. During this process, naphthalene being sublime changes into vapours leaving behind impurities. Vapour can be cooled by condensation. This process is very helpful in separating a volatile solid from a non-volatile solid.
How would you upscale your chemistry learning through
the knowledge of periodic table. Explain? (5 marks worth answer)
Explanation:
The periodic table brings order to information about the chemical elements. It helps chemists to understand why elements react as they do. Elements in the same group have similar chemical properties. This is because they have the same number of outer electrons and the same valency
A piece of wood displaces 12.5 mL of water and has a density of 0.97 g/ml. what is the mass of the piece of wood? what will happen if the wood is placed in water?
HELP PLEASE! ASAP YOUR DA BEST! 15 POINTS YALL
Density=0.97g/mL
Volume=12.5mL
[tex]\\ \sf \longmapsto Density=\dfrac{Mass}{Volume}[/tex]
[tex]\\ \rm\longmapsto Mass=Density(Volume)[/tex]
[tex]\\ \sf \longmapsto Mass=0.97(12.5)[/tex]
[tex]\\ \sf \longmapsto Mass=12.125g[/tex]
Which of the following should NOT be used to hold chemicals while they are being heated?
Question 5 options:
test tube
weigh boat
beaker
crucible
Answer: Weigh boat
Explanation:
they are disposable and will likely melt
Weigh boat among the following should not be used to hold chemicals while they are being heated ,therefore option (b) is correct.
What do you mean by weigh boats ?Weigh boats are ideal for general-purpose weighing, evaporating, dispensing, and storing applications. Compatible with balances and dryers, these pans support precise measurements.
A weigh boat is an open container often used in chemistry and bio chemistry. It is used if you want to weigh a sample very accurately.
A weigh boat is an object that is used to protect your balance from any object you want to weigh.
Weigh boat among the following should not be used to hold chemicals while they are being heated ,hence option (b) is correct.
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Một hỗn hợp X gồm CH3OH; C2H5OH; phenol có khối lượng 28,9 gam phản ứng vừa hết với 100ml dung dịch NaOH 2M. Phần trăm theo khối lượng phenol là ? Biết C = 12; O = 16; H = 1; Na = 23. *
Answer: bạn viết phương trình Phenol + NaOH
=> nNaOH = nPhenol = 0,2 mol
m Phenol = 0,2x94 = 18,8 gam
%mPhenol = 18,8/28,9% = 65,05
Explanation:
in the photoelectric effect, what happens when light hits the metal
Answer:
electrons are knocked off atoms, causing electricity to flow.
Explanation:
Can someone help me pls
What do you think nowadays computer engineer, civil engineer or electrical engineer which one is more demanded?
phương trình nào sau đây không đúng
Mg(OH)2 (t°)→ MgO+H2O
Fe(OH)2 (t°,chân không)→FeO+H2O
2Fe(OH)3 (t°)→Fe2O3+3H2O
2NaOH (t°)→Na2O+H2O
Phương trình NaOH sai nha
Use Charles's Law to solve the following problem. A sample of air has a volume of 550.0 mL at 106 °C. At what temperature will its volume be 700.0 mL at constant pressure?
a
482 K
b
63 °C
c
505 K
d
119 °C
Answer:
im not sure but i think its c
505 K
write the importance of exothermic reactions
Answer: An exothermic reaction is a "reaction for which the overall standard enthalpy change ΔH⚬ is negative." Exothermic reactions usually release heat and entail the replacement of weak bonds with stronger ones.
Exothermic reactions are important to forensic sciences and particularly to fire and explosion investigation. When a chemical reaction requires heat (rather than producing it) and results in cooling down the surroundings, it is conversely called endothermic.
Example-
Respiration is a series of exothermic reactions that occur in the mitochondria of living cells in order to release energy from food molecules. This energy can then be used to produce heat, for movement, growth, reproduction and active uptake.
Hope it helps
What is the [H+] if the pH of a solution is 3.20?
(in scientific notation)
Answer:
[H⁺] = [tex]6.3096[/tex]×[tex]10^{-4}[/tex] M
Explanation:
pH= - log[H⁺]
=> 3.2 = - log[H⁺]
=> [H⁺] = [tex]10^{-3.2}[/tex]
∴ [H⁺] = [tex]6.3096[/tex]×[tex]10^{-4}[/tex] M
pls mark it as brainliest
What are three ways that plastic pollution is harmful on land
Answer:
Plastic pollution are harmful on land because;
It can make human felt sick which is not healthy for us.Identify each transition in this flowchart as a chemical change or a physical change.
Answer:
so i think physical change
Which statement defines an ore?
Answer:
The third one
Explanation:
An ore is a naturally occurring solid material from which a metal or valuable mineral can be profitably extracted.
True or false. A car engine must have fossil fuels to work
Answer: False
Explanation:
It is not that it must have fossil fuels only because car can also work on hydro power and water. So it should be energy.
must click thanks and mark brainliest
Its fact that a car can also run on water and hydropower means that it does not necessarily need fossil fuels. Therefore, a car engine must have fossil fuels to work is false.
What are fossil fuels ?An extracted and burnt fossil fuel is a hydrocarbon-containing substance that naturally originated in the Earth's crust from the remnants of extinct plants and animals.
Natural gas, crude oil, and coal are the three primary fossil fuels. Fossil fuels are resources that resemble rocks, gases, or liquids that are burnt to produce electricity.
They are employed as energy sources in the electrical and transportation industries and include coal, natural gas, and oil. They are also a major contributor to global warming pollution.
Fossil fuels are used to generate energy, they are burnt to provide heat in homes, electricity in big power plants, and power for engines.
Thus, a car engine must have fossil fuels to work is false.
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9. What is useful in constructing scientific questions, methods, and explanations?
A. formaldehyde
B. a large research team
C. a very limited amount of time
D. creativity
Answer: C
creativity
Explanation:
C. Because the results of some experiments might not be explained by any
known theories.
Answer:
creativity
Explanation:
giúp tớ với, mình học lớp 9 ạ
Answer: broooo what is this
Explanation:
The levels of carbon dioxide in the atmosphere a. began decreasing when the burning of fossil fuels increased. b. are estimated to be higher than at any time in the past 420,000 years. c. are high but not higher than the highest estimated levels in the last 420,000 years. d. peaked around 1950 and have begun slowly decreasing since then.
The levels of carbon dioxide in the atmosphere are estimated to be higher than at any time in the past 420,000 years. That is option B
Carbon dioxide is a very harmful compound which is easily released into the atmosphere through burning of fossil fuels and other carbon compounds in plenty of air.
The released carbon dioxide rises to the upper atmosphere and blocks the radiation of solar energy back into the space. This precipitates a global temperature increase called the greenhouse effect.
According to Intergovernmental Panel on Climate Change (IPCC) in a current research discovered that CO2 concentration in the earth’s atmosphere is higher than at any point during the last 650,000 years. They where able to study this through the study of higher levels of CO2 concentration which coincide with higher temperatures.
Therefore the correct option is B which states that the levels of carbon dioxde in the atmosphere are estimated to be higher than at any time in the past 420,000 years.
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divide rs 120 I three parts which are in THE ratio of 1:2:3.
Answer:
20,40,60
Explanation:
Let the three parts be 1x, 2x and 3x
The the sum of three parts will be 1x+2x+3x = 120
6x=120
x=120/6
x=20
1x= 20x1=20
2x= 20x2=40
3x= 20x3=60
So 120 is divided in three parts that is 20,40,60
Answer From Gauth Math
can you help me please?
Explanation:
Physical changes only change the appearance of a substance, not its chemical composition.
Chemical changes cause a substance to change into an entirely substance with a new chemical formula.
Chemical changes are also known as chemical reactions. The “ingredients” of a reaction are called reactants, and the end results are called products
What are differences between viruses and bacteria?
Answer:
viruses are computer program that replicate itself and distribute itself to another computer but bacteria is micro organism that contaminate our food and can make us sick
What is an atomic mass unti
Explanation:
a unit of mass used to express atomic and molecular weights, equal to one twelfth of the mass of an atom of carbon-12.
Answer:
Atomic Mass Unit is also called Dalton. It is used to express atomic and molecular weight. It is defined as 1/12 of the mass of an unbound neutral atom of carbon.
what the recipe of momo
Answer:
Down is the recipe for momo..
Explanation:
recipe..
. Sieve the wheat flour carefully to remove lumps.
. Add water and knead the flour well to prepare a dough
. Remove the skin of the boiled potato ,cut into small pieces
. Heat the cooking oil in frying pan, and fry the pieces of onions cabbage green chili tomato pea etc.
. Prepare a mix veg stuffing by mixing potato other vegetables , green coriander and salt.
. Prepare a small balls of dough and roll it out of belna.
. Put 10 gm of mix vegetables stuff in the center of rolled dough and close it from all the sides to make a small ball.
. steam the momo for 10-15 minutes. After that it will be ready to serve.
. A sauce or pickle is usually eaten with momo.
Answer:
Explanation:
Sieve the wheat flour carefully to remove lumps.
Which option explains why this amino acid can act
both an acid and a base?
(1 point)
It contains both an amino functional group and a carboxyl functional group. In a solution, the amino group can
increase acidity, while the carboxyl group can decrease acidity
It contains both an amino functional group and a methyl functional group. In a solution, the amino group can
increase acidity, while the methyl group can decrease acidity
It contains both an amino functional group and a carboxyl functional group. In a solution, the amino group can
decrease acidity, while the carboxyl group can increase acidity
It contains both an amino functional group and a methyl functional group. In a solution, the amino group can
decrease acidity, while the methyl group can increase acidity
The correct answer is: It contains both an amino functional group and a carboxyl functional group. In a solution, the amino group can
decrease acidity, while the carboxyl group can increase acidity.
The carboxyl functional group is acidic while the amine group is basic.
In an amino acid, there are two functional groups;
The amine groupThe carboxyl groupThe carboxyl functional group is acidic because it contains a replaceable or ionizable hydrogen ion. The amine group on the other hand is capable of accepting a proton hence it is basic.
Therefore, In a solution, the amine group can decrease acidity, while the carboxyl group can increase acidity.
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differentiate between Physical and chemical changes
Answer:
In a physical change the appearance or form of the matter changes but the kind of matter in the substance does not. However in a chemical change, the kind of matter changes and at least one new substance with new properties is formed.
I HOPE THIS WILL HELP YOU IF NOT THEN SORRY HAVE A GREAT DAY:)Which natural resource is renewable?
coal
wind
topsoil
O oil
An example of natural resource that is renewable is wind. Details about natural resources can be found below.
What is natural resources?Natural resources are resources that cannot be exhausted i.e. can be replenished with time.
Examples of natural resources are as follows:
SunWindWaterForest treesTherefore, an example of natural resource that is renewable is wind.
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The natural resource that is renewable is wind. Therefore, option B is correct.
What are renewable resources?Renewable resources are natural resources that can be restocked or regenerated over a relatively short period of time, usually within a human lifetime. These resources are often contrasted with non-renewable resources, such as fossil fuels, which take millions of years to form and are finite in quantity.
Examples of renewable resources include solar energy, wind energy, hydroelectric power, geothermal energy, biomass, and tidal power.
These resources have the potential to provide energy and other materials indefinitely if used sustainably, making them an important part of efforts to move towards a more sustainable future. Therefore, option B is correct.
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