Answer:
Explanation:
Alexander Fleming's hypothesis was that the juice that was produced by the mold that appeared in the petri dishes was killing the bacteria growing there (streptococcus, meningococcus and the diphtheria bacillus).
Answer:
He thought the mold had released a chemical that prevented the bacteria’s growth.
Explanation:
Gradpoint
The _______ force between each planet and the Sun keeps the planets in orbit around the Sun.
Answer:
The Force of Gravity force between each planet and the Sun keeps the planets in orbit around the Sun.
Explanation:
How do you know a physical change has occurred when evaporating water produces gaseous water?
A
A chemical change has resulted in a new substance.
B
A chemical change has resulted in a change of state.
C
A physical change has resulted in a phase change, not a change in composition.
Answer:
Its b its the state not anything else
A physical change has occurred has occurred when evaporating water producing gaseous water as a physical change results in a phase change, not a change in composition.
What is a physical change?
Physical changes are defined as changes which affect only the form of a substance but not it's chemical composition. They are used to separate mixtures in to chemical components but cannot be used to separate compounds to simpler compounds.
Physical changes are always reversible using physical means and involve a change in the physical properties.Examples of physical changes include melting,boiling , change in texture, size,color,volume and density.Magnetism, crystallization, formation of alloys are all reversible and hence physical changes.
They involve only rearrangement of atoms and are often characterized to be changes which are reversible.
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Given the reaction:
NH3(g) + H2O() NH4+(aq) + OH–(aq)
Which is the conjugate acid-base pair?
A) H2O() and NH4+(aq)
B) H2O() and NH3(g)
C) NH3(g) and OH–(aq)
D) NH3(g) and NH4+(aq)
Which material can best be used to cast a footwear or tire impression?
A.) wax
B.) cement
C.) sulfur
D.) putty
Answer:
B.) cement
Explanation:
The commonest types of impression evidence found in crime scenes include footprints, tire tracks, bite marks and tool marks etc.These types of impression evidence can be used by crime scene investigators to link the suspects to the crime.
The impressions are usually cast using gypsum cement and other forms of casting tools to preserve the evidence and make it useful during any period in the course of the investigation.
What mass of copper is consumed in the reaction with hydrochloric acid if 10.0 g of gas is collected?
Answer:
317 g
Explanation:
Cu + 2HCl --> CuCl2 +H2
1 : 2 1 : 1
1 mole of Cu = 63.5 g
1 mole of H2 = 2g
1 mole Cu produces = 1 mole of H2
63.5 g of Cu produces = 2 g of H2
So
10 g of H2 will be produced from = (63.5/2)*10 = 317 g of Copper
Is the earth older than any of they rock layers
Answer:
no the rock was formed before the layers that we life on today
Explanation:
Why do we experience the changing of the seasons on earth
Answer:
Earth's axis and position around the sun.
Explanation:
Earth's tilted axis causes the seasons to change. Throughout the year, different parts of Earth acquire the Sun's most direct rays(Or heat) because of the orbital rotation of Earth. So, when the North Pole tilts toward the Sun, it's summer inside the Northern Hemisphere. And whilst the South Pole tilts towards the Sun, it is winter within the Northern Hemisphere and vise versa.
We experience the changing of the seasons on earth due to earth's changing relationship of the sun.
What causes seasons on earth?
Seasons happen because Earth's axis is tilted at an angle of about 23.4 degrees. And different parts of Earth receive more solar energy than others.Because of Earth's axial tilt (obliquity), our planet orbits the Sun on a slant which means different areas of Earth point toward or away from the Sun at different times of the year.
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why natural fas is not used as a bottled gas or as a motor fuel?
Answer:
Natural gas is an odorless, gaseous mixture of hydrocarbons—predominantly made up of methane (CH4). It accounts for about 30% of the energy used in the United States. About 40% of the fuel goes to electric power production and the remaining is split between residential and commercial uses, such as heating and cooking, and industrial uses. Although natural gas is a proven, reliable alternative fuel that has long been used to power natural gas vehicles, only about two-tenths of 1% is used for transportation fuel.
The vast majority of natural gas in the United States is considered a fossil fuel because it is made from sources formed over millions of years by the action of heat and pressure on organic materials. Alternatively, renewable natural gas (RNG), also known as biomethane, is a pipeline-quality vehicle fuel produced from organic materials—such as waste from landfills and livestock—through anaerobic digestion. RNG qualifies as an advanced biofuel under the Renewable Fuel Standard.
Because RNG is chemically identical to fossil-derived conventional natural gas, it can use the existing natural gas distribution system and must be compressed or liquefied for use in vehicles.
CNG and LNG as Alternative Transportation Fuels
Two forms of natural gas are currently used in vehicles: compressed natural gas (CNG) and liquefied natural gas (LNG). Both are domestically produced, relatively low priced, and commercially available. Considered alternative fuels under the Energy Policy Act of 1992, CNG and LNG are sold in units of gasoline or diesel gallon equivalents (GGEs or DGEs) based on the energy content of a gallon of gasoline or diesel fuel.
Compressed Natural Gas
CNG is produced by compressing natural gas to less than 1% of its volume at standard atmospheric pressure. To provide adequate driving range, CNG is stored onboard a vehicle in a compressed gaseous state at a pressure of up to 3,600 pounds per square inch.
CNG is used in light-, medium-, and heavy-duty applications. A CNG-powered vehicle gets about the same fuel economy as a conventional gasoline vehicle on a GGE basis. One GGE equals about 5.66 pounds of CNG.
Liquefied Natural Gas
LNG is natural gas in its liquid form. LNG is produced by purifying natural gas and super-cooling it to -260°F to turn it into a liquid. During the process known as liquefaction, natural gas is cooled below its boiling point, removing most of the extraneous compounds found in the fuel. The remaining natural gas is primarily methane with small amounts of other hydrocarbons.
Because of LNG's relatively high production cost, as well as the need to store it in expensive cryogenic tanks, the fuel's widespread use in commercial applications has been limited. LNG must be kept at cold temperatures and is stored in double-walled, vacuum-insulated pressure vessels. LNG is suitable for trucks that require longer ranges because liquid is denser than gas and, therefore, more energy can be stored by volume. LNG is typically used in medium- and heavy-duty vehicles. One GGE equals about 1.5 gallons of LNG.
Which of the following is a product found in the chemical equation below?
Answer: [tex]2H_2O[/tex] is a product found in the chemical equation
Explanation:
The given balanced chemical equation is as follows:
[tex]CH_3SH+4O_2\rightarrow CO_2+SO_2+2H_2O[/tex]
A chemical reaction is represented by writing the chemical formula of the reactants on the left side of the arrow and the products on the right side of the arrow.
Here 1 mole of [tex]CH_3SH[/tex] and 4 moles of [tex]O_2[/tex] are the reactants and 1 mole of [tex]CO_2[/tex] , 1 mole of [tex]SO_2[/tex] and 2 moles of [tex]H_2O[/tex] are the products.
Thus from the given options, [tex]2H_2O[/tex] are products
Which planet in the solar system is least dense
Answer:
Saturn
Explanation:
Answer:
Saturn
Explanation:
NEED ASAP WILL MARK BRAINLIEST ON TIMER
hi A student determines that she used 0.0665 mol of sodium hydroxide (NaOH) to completely titrate 25.00 mL of sulfuric acid solution (H2SO4). What is the molarity of the sulfuric acid?
0.00131 M
0.00262 M
1.31 M
2.62 M
Answer:
The answer is 2.660 mol/l
Explanation:
Given: n= 0.0665, v= 25.00ml
Required: C
C (molarity)= n (of solute)/ v (of solvent) [ standard unit: mol/l]
First convert volume of solvent in its standard unit, i.e. litres(L)
v= 25.00ml/1000= 0.02500L
C = 0.0665 mol / 0.02500 L= 2.660 mL (In proper significant digits i.e. 4 sigdigs)
Therefore, The molarity of the sulfuric acid is 2.660 mol/L :)
If the pH indicator bromothymol blue was added to the nitric acid solution, it's colour would be?
Answer:
Yellow
Explanation:
Thymol blue has a brownish-green or reddish-brown color and is a good pH indicator. It changes from red to yellow at a pH 1.2–2.8 ( acidic) and then from yellow to blue at a pH of 8.0–9.6( alkaline).
Nitric acid is a strong acid which means the pH indicator will change to yellow.
5.2 g of HCl are dissolved in 25 mL of solution. What is the molarity?
Answer:
The molarity is 5.7 moles per dm^3
Explanation:
Molarity is calculated in units of moles per dm^3 or simply moles per liter.
What this means is that to get the molarity, we simply find the number of moles and divide by the volume.
Since we are given the mass, we need to find the number of moles first.
Mathematically, the number of moles = mass/molar mass
The molar mass of HCl is 1 + 35.5 = 36.5 g/mol
The number of moles contained in 5.2g of HCl = 5.2/36.5 = 0.1425 moles
Now, we also need to convert the the volume to liters too.
1000 ml = 1L
25ml = xL
x * 1000 = 25
x = 25/1000 = 0.025 L
the molarity is thus 0.1425/0.025 = 5.7 mol/dm^3
describe the law of conservation of momentum
Name the following Compounds
Alkane C-C
Answer:
Alkanes
Explanation:
Compounds with a saturated hydrocarbon chain i.e having only single bonds between the atoms and is composed entirely of carbon and hydrogen is called as alkane.
The general formula of alkane is CnH2n+2.
Alkanes have no double or triple bonds and hence they have maximum number of carbon to hydrogen covalent bonds. While in case of alkenes there exists double bond and in case of alkynes exists triple bonds
What is the pH of a 3.50 x 10^-3 M NaOH solution
Answer:
11.54
Explanation:
-log(3.50*10^-3) = 2.46 pOH
pH = 14 - pOH
pH = 11.54
A woolly mammoth was found in 1999 buried in the frozen soil of the Siberian tundra. Carbon-14 dating indicated that it had died about 20,000 years ago. Many fossils represent only the partial remains of organisms. However, a complete mammoth with bones, skin, hair, and internal organs intact represented a unique opportunity for scientists to investigate the lifestyle of this animal and the environment in which it lived. The low permeability of the tundra soil helped to preserve the mammoth. Explain why the tundra soil has a low permeability.
Tundra soils are formed at high latitudes which leaves the tundra always very cold. Tundra soils are generally frozen, and are classifed as Gelisols (this means that permafrost are within 100 cm of the soil surface). These permafrost are as a result of the freezing by winter of the underground water that was accumulated in summer. These soils freeze and thaw alot and as result of that, moisture do not permeate the soil easily. Also, due to this harsh temperature and underground permafrost, most organisms that died in the tundra are preserved within the soil.
can u answer this?
Mass: 386 g
Volume: 20 cm to the third power
Density: ?
Answer:
Calculate density
Weight/mass
386
g
Volume
20
cm³
Density
19,300
kg/m³
Explanation:
Complete the sentences to describe the structure of DNA.
The shape of the DNA molecule is called a double
The backbone of DNA is made of
molecules and phosphate molecules
The "rungs" of DNA are made of
Answer:
helix
sugar-phosphate
four nitrogen bases that are adenine, thymine, guanine, cytosine
The shape of the DNA molecule is called a double helix. The backbone of DNA is made of sugar-phosphate molecules and phosphate molecules.
What is DNA?Deoxyribonucleic acid, or DNA, is an organic molecule with a complicated molecular architecture that is present in all prokaryotic or eukaryotic cells, as well as in a variety of viruses. For the transfer of inherited traits, DNA codes genetic information. Despite the fact that the molecule DNA was initially identified in 1869, its significance for inherited characteristics was not shown until 1943.
James Watson and Francis Crick discovered that the structure of DNA consists of a double-helix polymer, a spiral made up of two DNA strands twisted around each other. The shape of the DNA molecule is called a double helix. The backbone of DNA is made of sugar-phosphate molecules and phosphate molecules. The "rungs" of DNA are made of four nitrogen bases that are adenine, thymine, guanine, cytosine.
Therefore, the shape of the DNA molecule is called a double helix. The backbone of DNA is made of sugar-phosphate molecules and phosphate molecules.
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Give the formula for the alkane containing 500 carbons.
Answer:
1002
Explanation:
[tex]C_{2n}[/tex][tex]H_{2n+2}[/tex]
500 multiply by 2 add 2
The chemical formula of an alkane with 500 carbons is C₅₀₀H₁₀₀₂ as the general formula of alkanes is C[tex]_n[/tex]H[tex]_2n[/tex][tex]_+2[/tex].
What is chemical formula?Chemical formula is a way of representing the number of atoms present in a compound or molecule.It is written with the help of symbols of elements. It also makes use of brackets and subscripts.
Subscripts are used to denote number of atoms of each element and brackets indicate presence of group of atoms. Chemical formula does not contain words. Chemical formula in the simplest form is called empirical formula.
It is not the same as structural formula and does not have any information regarding structure.It does not provide any information regarding structure of molecule as obtained in structural formula.
There are four types of chemical formula:
1)empirical formula
2) structural formula
3)condensed formula
4)molecular formula
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Which level of ecological organization includes both biotic and abiotic factors
The answer is Ecosystem
Answer:
ecosystem
Explanation:
i took it on edge 2021 and got 100
1.
PART A: In paragraph 2, what does the phrase "miners of all shapes and sizes" mean? [R14]
A Many people were invited.
B. People with supplies traveled to the Yukon.
C. People experienced discrimination.
D. Many types of people traveled to the Yukon.
Answer:
A.
Explanation:
Miners were happy due to the result of the gold rush. they labored very hard for very little profit. Working in the Yukon Territory was not safe. To reach it, the ground had to be dug. Then the dirt had to be removed to get the gold.
In paragraph 2, what does the phrase "miners of all shapes and sizes" mean that many people were invited. This included food, clothing, transportation equipment, etc.
What determines how fast a substance will dissolve
Answer:
(1) the surface area of the solute,
(2) the temperature of the solvent,
(3) the amount of agitation that occurs when the solute and the solvent are mixed.
Explanation:
What happens to the chemical structure of water when it changes states
Answer:
When water changes to a solid or gas, it's said that water changes to a different state of matter
Explanation:
Even when water physical form changes, the molecules stay the same. Water's molecules contains two hydrogen atoms that is bonded with one oxygen atom.
does an oxygen atom form two covalent bonds?
Answer:
yes
Explanation:
Two covalent bonds form between the two oxygen atoms because oxygen requires two shared electrons to fill its outermost shell.
what do you mean by elementary and their classification
Answer:
The Classification of elementary students and the basis of their state of mind determines how they are and how they react to specific things.
Explanation:
The classification of that specific person depends on their qualifications
Define Kelvin's Temperature.
Answer:
Is an absolute temperature scale with zero at absolute zero
Tricky please help !!!!!!!!
Which of the following objects has the greatest kinetic energy
during a nuclear reaction, what is mass converted into?
Answer:
The mass is converted to energy to cause the mushroom cloud you woud see
Explanation: