the most important methods are A and B
When using a scientific method, two of the most important steps are stating the problem and making a hypothesis. So the correct option is B.
What is a scientific hypothesis?Any kind of biological investigation will generally start with an observation. An observation is something that catches the attention of the biologist. For example, a microbiologist notices that a bacteria is not stained by any stain and wonder why this is happening.
The base of biology and other sciences have a problem-solving approach called the scientific method. The scientific method has five main steps and an additional feedback step:
Making an observation.Asking a question.Forming a hypothesis or testable explanation.Making a prediction based on the hypothesis.Testing the prediction.Iterating the use of the results to make new hypotheses or predictions.Therefore, when using a scientific method, two of the most important steps are stating the problem and making a hypothesis. So the correct option is B.
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Which information must be known about a compound to find the molecular formula from the empirical formula?
The molecular mass of the compound is required to calculate the molecular formula from the empirical formula.
What is a molecular formula?A chemical formula that gives the total number of atoms of each element in each molecule of a substance.
Dividing the molar mass of the compound by the empirical formula mass. The result should be a whole number or very close to a whole number. Multiplying all the subscripts in the empirical formula by the whole number will give the resultant molecular formula.
Hence, the molecular mass of the compound is required to calculate the molecular formula from the empirical formula.
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Select the correct answer. the compound diborane can be used as a rocket propellant. what is the percent composition of boron in diborane (b2h6)? a. 22% b. 25% c. 39% d. 75% e. 78%
The percent composition of boron in diborane (b2h6) is 78% because the mass of boron is higher than hydrogen atom.
What is diborane?Diborane is a poisonous, reactive gas that is produced by the action of acids on borides. Diborane is used as a reducing agent for making other chemicals and also act as a catalyst.
So we can conclude that The percent composition of boron in diborane (b2h6) is 78% because the mass of boron is higher than hydrogen atom.
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The compound diborane can be used as a rocket propellant. the percentage composition of boron in diborane (B2H6) is 75%. Option D. This is further explained below.
What is the compound diborane?Generally, Diborane is simply defined as a compound having the molecular formula B2H6, Diborane is more often known as diborane.
In conclusion, As a rocket fuel, diborane is a useful chemical. Diborane (B2H6) contains 75 percent boron by weight.
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What is a renewable resources
Answer: A renewable resource is a resource that can easily be replaced over a short amount of time.
Explanation: Unlike the non-renewable resources, they can be replenished.
Examples for non-renewable: coal, oil, and fossil fuels.
Examples for renewable resources: Wind, nuclear, solar power, and water.
How many moles of naoh will react with 13.5 moles of k3po4
Answer: 40.5 mol
Explanation:
Since this is a double replacement reaction, the unbalanced equation is something like follows:
[tex]\text{K}_{3}\text{PO}_{4}+\text{NaOH} \longrightarrow \text{KOH}+\text{Na}_{3}\text{PO}_{4}[/tex]
Balancing this equation,
[tex]\text{K}_{3}\text{PO}_{4}+3\text{NaOH} \longrightarrow 3\text{KOH}+\text{Na}_{3}\text{PO}_{4}[/tex]
From this equation, we can conclude that for every 3 moles of sodium hydroxide consumed, 1 mole of potassium phosphate is consumed.
This means the answer is 13.5(3)=40.5 mol
Which are examples of biotic factors? Select three options.
rotting log
stream water
dead leaves
bacteria
soil
The biotic factors are bacteria soil, dead leaves, and stream water.
What is an abiotic factor?An abiotic factor is a non-living part of an ecosystem that shapes its environment.
Biotic and abiotic factors make up a community via interaction.
Biotic factors are considered living things (having "life") while abiotic factors are simply non-living things.
The dead leaves of plants are an abiotic factor, the bacteria in soil are living matter and stream flowing, etc.
Hence, the biotic factors are bacteria soil, dead leaves, and stream water.
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A piece of copper wire is 180 cm long. how long is the wire in millimeters? how many
40 mm segments of wire can be cut from the length
Centimeters and millimeters are both interconvertible units to measure length. The conversion factor is as follows:
1 centimetre = 10 millimetres
This means that if a copper wire is 180cm long, the wire would be;
180 × 10 = 1800mm long
Also, the number of 40 mm segments of wire that can be cut from the length is calculated as follows:
1800mm/40mm = 45
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2.
An ion has 15 protons, 16 neutrons, and 18 electrons.
a.
b.
What is the atomic number?
What is the mass number?
What is the overall charge?
d. Write the isotope notation.
C.
Explain the process of how clouds form
Answer:
clouds are formed when the invisible water vapour in the air condenses into visible water droplets or ice crystal
Answer: Clouds need two things to form: cool air and particles on which water vapor can condense. Clouds form as air cools. Cold air cannot hold as much water vapor, so the water vapor condenses. Water vapor condenses on small particles in the atmosphere, such as smoke, salt, and dust. As a result, clouds form.
Explanation: correct on edge
An element A combines with element B. The electrons are transferred from the atom A to the atom B. .
(a) What is the nature of bond between A and B?
(b) What are the two main properties expected compound AB?
(c) What happens if this compound is dissolved in water? To
(a) The nature of bond between A and B is an ionic bond.
(b) The two main properties of the ionic compounds are:
Ionic Compounds have high boiling and melting points as they're very strong and require a lot of energy to break.The electrostatic forces of attraction between oppositely charged ions lead to the formation of ions.(c) If the ionic compound is dissolved in water, the ions in the solid separate and disperse uniformly
What is an ionic compound?Ionic compounds contain ions and are held together by the attractive forces among the oppositely charged ions.
An ionic bond is formed by the complete transfer of some electrons from one atom to another. The atom losing one or more electrons becomes a cation—a positively charged ion.
In ionic bonds, the metal loses electrons to become a positively charged cation, whereas the nonmetal accepts those electrons to become a negatively charged anion.
When ionic compounds dissolve in water, the ions in the solid separate and disperse uniformly throughout the solution.
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NEED HELP!!!
How many moles of magnesium is 3.01 x 1022 atoms of calcium?
preferably a step by step answer....thank u<3
Answer:
0.03 mol
Explanation:
The equation relating the number of moles and number of atoms is:
Number of atoms = number of moles × 6.02 × 10²³
[6.02 × 10²³ is the Avogadro's constant and is the number of particles in 1 mole of any substance.]
By rearranging the equation, we can find the number of moles of calcium.
Number of moles = (3.01 × 10²²) ÷ (6.02 × 10²³)
Number of moles = 0.05 moles of calcium
Now the only data we know about these two elements are their Mr values, so we are going to find the number of moles of magnesium using ratio.
Moles : Mr
0.05 mol : 40.1
x : 24.3
[we are going to assume that x is the number of moles of magnesium that we have to find out.]
Cross multiply the ratios.
40.1x = 0.05 × 24.3
x = 1.215 ÷ 40.1 = 0.03 mol
How many cells are in bacteria? (any links added will be reported!)
Answer:
There is 1 cell in bacteria and it is called Prokaryotic cells
Explanation:
Identify the genotypic and phenotypic ratios of offspring in the standard monohybrid cross.
Parent 1: _______________
Garden pea plant with homozygous gene pair for round seed
Garden pea plant with homozygous gene pair for wrinkled seed
Genotype (Parent 1): _______________
RR
rr
Parent 2: _______________
Garden pea plant with homozygous gene pair for round seed
Garden pea plant with heterozygous gene pair for round seed
Genotype (Parent 2): _______________
RR
Rr
The genotype and phenotype ratio for the first cross will be 100% Rr and 100% round, while the second cross will be 1RR:1Rr, 50/50 round and wrinkled respectively.
Monohybrid crossesAssuming that the seed shape allele is R(r).
For the first cross: RR x rr
Rr Rr Rr Rr
Genotype ratio = 100% Rr
Phenotype ratio = 100% round
For the second cross: RR x Rr
RR Rr RR Rr
Genotype ratio = 1RR : 1Rr
Phenotype ratio = 50% round and 20% wrinkled.
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Please hurry! classify the following as a
heterogeneous mixture,
homogeneous mixture (solution), or
a pure substance:
s'mores
a. heterogeneous mixture
b. homogeneous mixture/solution
c. pure substance
Answer:it’s A
Explanation:
Smores are made up of different materials are made by squashing a hot, oozing marshmallow with chocolate between two Graham crackers. This is heterogeneous mixture.
What are S’mores?A dessert consisting usually of toasted marshmallow and pieces of chocolate bar sandwiched between two graham crackers. Graham crackers, marshmallows, and chocolate are used to make s'mores. Homogenous mixture: A homogeneous mixture is a mixture of substances blended so thoroughly that you cannot see individual substances. Example- A mixture of salt and water, A mixture of water and sugar.
Heterogeneous mixture: A heterogeneous mixture is a mixture of two or more compounds. Example- Vegetable soup is a heterogeneous mixture. Any given spoonful of soup will contain varying amounts of the different vegetables.
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At 25oc, enough distilled water is added to a 30.0 ml sample of hno3(aq) with a ph of 4.20 so that the final ph of the diluted solution is 5.20. the volume of distilled water added to the original solution is closest to
The volume of distilled water added to the original solution is closest to 300.0 ml.
What is pH?The potential of hydrogen is a measure of the acidity or alkalinity of a solution equal to the common logarithm of the reciprocal of the concentration of hydrogen ions in moles per cubic decimetre of solution.
Concentration of 30.0 ml sample of [tex]HNO_3[/tex] solution is = 6.31 X [tex]10^{-5}[/tex] M
pH of diluted [tex]HNO_3[/tex] solution = 5.20
We know that,
[tex]pH= -Log [H^+][/tex]
[tex]5.20= -Log [H^+][/tex]
[tex][H^+] = 10^{-5.2} = 6.31 X 10^{-6} M[/tex]
Hence, concentration of unknown diluted [tex]HNO_3[/tex] solution is 6.31 X [tex]10^{-5}[/tex] M.
By the use of the equation:
[tex]HNO_3[/tex] Concentration = [tex]HNO_3[/tex] diluted
[tex]V_{dil} = \frac{(C_conc X V_conc)}{(C_{dil})}[/tex]
[tex]V_{dil}[/tex] = (6.31 X [tex]10^{-5}[/tex] M X 30.0 ml) ÷ (6.31 X 10^{-6} M)
[tex]V_{dil} = 300.0 ml[/tex]
Hence, the volume of distilled water added to the original solution is closest to 300.0 ml.
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(You do) If you have 47.2 mol of Na available, along with an excess of Cl₂, how many grams of NaCl can you produce?
Equation: 2Na+Cl2=2NaCl
Answer:
2,760 grams NaCl
Explanation:
To find grams of NaCl, you need to (1) convert moles of Na to moles of NaCl (via mole-to-mole ratio from reaction) and (2) convert moles of NaCl to grams (via molar mass from periodic table). The final answer should have 3 significant figures based on the given measurement.
2 Na + Cl₂ --> 2 NaCl
Molar Mass (NaCl) = 22.99 g/mol + 35.45 g/mol
Molar Mass (NaCl) = 58.44 g/mol
47.2 moles Na 2 moles NaCl 58.44 grams
---------------------- x --------------------------- x ------------------------- =
2 moles Na 1 mole NaCl
= 2,758.368 grams NaCl
= 2,760 grams NaCl
What best describes the relationship between photosynthesis and cellular respiration? a.Celluar respiration and photosynthesis are identical reactions. b. photosynthesis is just like celluar respiration, but oxygen is involved. c. celluar respiration and photosynthesis are not related at all. d. photosynthesis and celluar respiration are opposite reactions.
The statement 'photosynthesis and cellular respiration are opposite reactions' best describes the relationship between photosynthesis and cellular respiration.
What is cellular respiration?Cellular respiration is a chemical process where foods and oxygen are used to generate ATP in aerobic conditions.
Conversely, photosynthesis is a chemical process where light and carbon dioxide are used to generate chemical energy.
In conclusion, the statement 'photosynthesis and cellular respiration are opposite reactions' best describes the relationship between photosynthesis and cellular respiration.
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How might this graph be different if the farmers had grown a wide variety of potato plants or had included other crops in their fields? Construct an explanation to support your answer. Construct an explanation to support your answer.
The graph would not have plummeted if various species were planted due to improvement of the potato crops.
What is variety?
The term variety has to do with the planting of different species of plants on the same farm. We know that the planting of different species of the same crop helps to improve the resistance to diseases of a plant.
Hence, the graph would not have plummeted if various species were planted due to improvement of the potato crops.
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what is the colour of our oxygen
best answer will get 30 points
Answer:
colourless
Explanation:
although the gaseous form of oxygen is colourless
when it liquefies it turns into a blue fluid.
hope this helps:)
Which of the following numbers is equal to the value shown in scientific
notation below?
1.9 x 10-2
A.0.0019
B.0.019
C.0.19
D. 0.00019
Explanation:
the answer for the above
is b)0.019
Why the bond angle of ammonium is larger than water?
Answer:
This repulsion is stronger than the repulsion between the lone pair and the three bond pairs on the nitrogen atom. Since the repulsions on the bond pairs in H2O molecule are greater than that in NH3 the bond angle in water is less than that of ammonia.
Determine the molar mass of a 0.458-gram sample of gas having a volume of 1.20 l at 287 k and 0.980 atm. group of answer choices 1.954 g/mol 73.6 g/mol 7.18 g/mol 9.17 g/mol
Considering the ideal gas law and the definition of molar mass, the molar mass of the sample of gas is 9.17 [tex]\frac{g}{mol}[/tex].
Ideal gas lawAn ideal gas is a theoretical gas that is considered to be composed of randomly moving point particles that do not interact with each other. Gases in general are ideal when they are at high temperatures and low pressures.
The pressure, P, the temperature, T, and the volume, V, of an ideal gas, are related by a simple formula called the ideal gas law:
P×V = n×R×T
where:
P is the gas pressure.V is the volume that occupies.T is its temperature.R is the ideal gas constant. The universal constant of ideal gases R has the same value for all gaseous substances.n is the number of moles of the gas. Definition of molar massThe molar mass of substance is a property defined as its mass per unit quantity of substance, in other words, molar mass is the amount of mass that a substance contains in one mole.
Molar mass of the sample of gasIn this case you know:
P= 0.980 armV= 1.20 LT= 287 KR= 0.082 [tex]\frac{atmL}{molK}[/tex]n= ?Replacing in the ideal gas law:
0.980 atm× 1.20 L= n× 0.082[tex]\frac{atmL}{molK}[/tex]× 287 K
Solving:
(0.980 atm× 1.20 L)÷ (0.082[tex]\frac{atmL}{molK}[/tex]× 287 K)= n
0.04997 moles= n
On the other hand, you know that the mass of the sample of gas is 0.458 grams. Replacing in the definition of molar mass:
[tex]molar mass=\frac{0.458 grams}{0.04997 moles}[/tex]
Solving:
molar mass= 9.17 [tex]\frac{g}{mol}[/tex]
Finally, the molar mass of the sample of gas is 9.17 [tex]\frac{g}{mol}[/tex].
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What is true about the breakdown of starch?
a.
Animals, but not plants, can break down starch.
b.
Organisms break down starch into carbon, hydrogen, and oxygen atoms.
C. Organisms break down starch into carbohydrate subunits.
d.
Starch breakdown is not a chemical reaction
Answer:
Option C
Explanation:
Organisms break down starch into glucose
Which is a carbohydrate subunitThe organisms are found in our digestive system helps in break down of starch and turns them into glucoseAnswer:
Organisms break down starch into carbohydrate subunits.
Explanation:
Starch is a necessary amount of our bodyIt is used as an carbohydrate subunit well known as glucoseIt is converted through organismsSo option C is correct
Which statement defines specific heat capacity for a given sample
The statement that defines the specific heat capacity for a given sample is the quantity of heat that is required to raise 1 g of the sample by 1°C (Kelvin) at a constant pressure.
What is specific heat capacity?Specific heat capacity is the of heat to increase the temperature per unit mass.
The formula to calculate the specific heat is Q = mct.
The options are attached here:
The temperature of a given sample is 1 %.The temperature that a given sample can withstand.The quantity of heat that is required to raise the sample's temperature by 1 °C1 °C (Kelvin).The quantity of heat that is required to raise 1 g of the sample by 1°C (Kelvin) at a constant pressure.Thus, the correct option is 4. The quantity of heat that is required to raise 1 g of the sample by 1°C (Kelvin) at a constant pressure.
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Why is water used as a solvent in many solutions?
A Water dissolves other water molecules.
B Water dissolves any chemical.
C Water dissolves nonpar molecules.
D Water dissolves polar molecules.
O A
OB
O C
O D
how do gases exert pressure into a cylindrical container
Answer: The molecules are continually colliding with each other and with the walls of the container. When a molecule collides with the wall, they exert small force on the wall The pressure exerted by the gas is due to the sum of all these collision forces. The more particles that hit the walls, the higher the pressure. If a gas is heated up, its particles move around more quickly. They hit the walls of their container harder and more often. This increases the pressure. Sometimes the pressure gets so great that the container bursts.
Explanation:
Answer:
When a molecule collides with the wall, they exert small force on the wall The pressure exerted by the gas is due to the sum of all these collision forces.
Explanation:
The molecules are continually colliding with each other and with the walls of the container. When a molecule collides with the wall, they exert small force on the wall The pressure exerted by the gas is due to the sum of all these collision forces. The more particles that hit the walls, the higher the pressure.
Describe the properties of alkali metals. based on their electronic arrangement, explain whether they exist alone in nature.
The alkali metals can't exist alone in nature because of incomplete outermost shell of alkali metals.
What are the properties of alkali metals?The alkali metals have the high thermal and electrical conductivity. It has high lustre, ductility, and malleability as compared to other materials. Each alkali metal atom has one electron in its outermost shell which make more reactive.
So we can conclude that the alkali metals can't exist alone in nature because of incomplete outermost shell of alkali metals.
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James Joule showed that _______ was a form of energy.
Answer:
Heat
Explanation:
He proved that heat was a form of energy. That is why the Joule (1 N*m or 1 kg*m^2/s^2) is the SI unit of energy. We now know that heat energy is a form of kinetic energy associated with temperature changes due to the vibrational motion in matter.
What health benefits can you get from consuming fiber? (select all that apply.)
soluble fiber can be absorbed into your skin to increase skin cells.
fiber helps digestion and can prevent constipation.
fiber can help create red blood cells.
soluble fiber helps lower cholesterol, which may prevent heart disease.
Answer:
Above all are correct answer.
some other benefits are like, Dietary fiber increases the weight and size of your stool and softens
Answer:
I Think its fiber helps digestion and can prevent constipation.and soluble fiber helps lower cholesterol, which may prevent heart disease.
Explanation:
A sample of helium gas has a volume of 6.50l at a pressure of 845 mmhg and a temperature of 25oc. what is the pressure of the gas in atm when the volume and temperature of the gas sample are changed to 1850 ml and 325 k
Answer:
4.25atm
Explanation:
[tex]\frac{P1V1}{T1}\\[/tex]=[tex]\frac{P2V2}{T2}[/tex]
where ,
p1 =845/760=1.11atm
v1=6.50l
t1=25c +273k=298k
p2=?
v2=1850/1000=1.85l
t2=325k
so answer is 4.25 atm
Perform the following
mathematical operation, and
report the answer to the
correct number of significant
figures.
3.96 * 0.1159 = [?]
The answer to the problem 3.96 * 0.1159 is : 0.459 (3 significant figures)
Meaning of Significant figures and the rule of engagementSignificant figures can be defined as numbers in a group of numbers that place number in the right value or worth.
Significant figures defined the value of measurement of a particular number.
The rules of engagement in this case is the set of rules or laid down principles that direct how we interact with this significant figures and how they are used.
For this case the significant figures of the product will be the same as the figure with the least significant figure in the multiplication.
In conclusion, The answer to the problem 3.96 * 0.1159 is : 0.459 (3 significant figures)
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