Answer:
Iron has four naturally-occurring stable isotopes, 54Fe, 56Fe, 57Fe and 58Fe. The relative abundances of the Fe isotopes in nature are approximately 54Fe (5.8%), 56Fe (91.7%), 57Fe (2.2%) and 58Fe (0.3%).
An atom has 30 protons and 30 neutrons. What is its mass number?
Mass number=No of protons+No of neutrons
[tex]\\ \sf\longmapsto Mass\:No=30+30[/tex]
[tex]\\ \sf\longmapsto Mass\:No=60[/tex]
Explanation:
Here,
Protons(p+)=30
Neutrons(N⁰)=30
We know,
Atomic mass(z)=(P+)+(N⁰)
=30+30
=60
Please help me answer this question
Answer:
d=m/v d=0.94
Explanation:
^^^^^^&&&&^^^^
calculate the density of the object that has a mass of 5.0 g and occupies the volume of 10.0 cm3
The procedure was applied to a new sample of 9.00 milliliters of the liquid mixture to extract component C. Due to the loss of volume from the procedure, the extracted volume of component C was only 90.0% of the original volume of this component. What was the extracted volume of component C, in milliliters
Percentage volume of substance in a mixture can be obtained by the following equation:
[tex]Percentage volume = \frac{Volume of sub.}{Total Volume} * 100\\\\[/tex]
Considering the question given above, the following data were obtained:
Total volume of mixture = 9 mL
Percentage of C extracted = 90%
Volume of C extracted =?
[tex]Percentage of C = \frac{Volume of C }{Total Volume} \\\\90 percent = \frac{Volume of C}{9}[/tex]
Cross multiply
Volume of C = 90% × 9
Volume C = 0.9 × 9
Volume of C = 8.1 mLTherefore, the volume of C extracted is 8.1 mL
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Polymers are long chains of:
A. crystals.
B. molecules.
C. simple molecules
D. atoms
Answer:
The answer should be Molecules.
Explanation:
Polymers are said to be synthetic or natural substances that are formed by joining the monomeric units together by bonds. They are long chains of molecules. Thus, option B is correct.
What are polymers?Polymers are macromolecules that are large and big in size that is composed of multiple chemical units of various molecules linked by chemical bonds. These substances can be natural or man-made.
The polymers are composed of monomeric units that are molecules like the starch polymer made of glucose monomeric units linked by the glycosidic linkages. They are complex and tough structures that often provide structural support and protection.
Proteins, carbohydrates, lipids, and nucleotides are polymers composed of amino acids, sugar, fatty acids, and nucleic acids. Polymers are involved in various functions in living organisms.
Therefore, option B. molecules make long chains of polymers.
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The orbit of a planet is an ellipse with the sunat one of the foci.. This is Kepler's........ second law third law first law
Answer:
its keplers first law
Explanation:
answer from gauth math
why does beryllium not liberate hydrogen from acid readily
6.3 gram of HNO3 as mass of nitrate
Moles of HNO 3
= 6.3/63 = 0.1 moles
HNO3 has 1 atom of H , 1 atom of N , 3 atoms of O
No of atoms = moles of molecule × atomicity of atom × avogadro number
No of atoms of H =0.1×1×6.023×10^23
= 6.023×10^22
No of atoms of N =0.1×1×6.023×10^23
= 6.023×10 ^22
No of atoms of O =0.1×3×6.023×10 ^23
= 18.069×10 ^22
5. A Brønsted-Lowry acid
A. is any species that donates a proton.
B. is any species that accepts a proton.
C. has a lower pH than vinegar.
D. is limited to aqueous solutions.
Answer:
A. is any species that donates a proton.Explanation:
A Bronsted-Lowry acid is a chemical species that donates one or more hydrogen ions in a reaction.
In contrast, a Bronsted-Lowry base accepts hydrogen ions.
What are your main fears about this class (if any)?
Answer:
sitting n front of class
reading out loud
and being stressed
and being bullied
Explanation:
Use VSEPR Theory to predict the molecular geometry around the central atom in each of the following molecules. Which of the following molecular geometries are correct?
1. XeF4, square planar
2. ICI., tetrahedral
3. SF4, seesaw
a. 1 and 2
b. 3 only
c. 1 and 3
d. 2 only
e. 1, 2 and 3
Where did you put H an He? What are your reasoning for placement?
Answer:
On the placement of hydrogen and helium in the periodic system
H1=1
He2=2
Determine the redox reaction represented by the following cell notation: Mg(s) | Mg2 (aq) || Cu2 (aq) | Cu(s)
What are precautions to be taken when doing titrations? A-Make sure to always vigorously shake that flask after every drop if the end point is still unknown. It may be that the remaining volume of the titrant needed to reach the end point is just adhering on the wall. This is to ensure accuracy. B-The amounts of solid and liquid should be weighed and pipetted with high accurac This is because all the data that will be produced will mainly depend on this. C- If the end point is unknown, dropwise addition of the titrant is recommended. D- Always make sure that the indicator is added. E- All of the above
Answer:
E
Explanation:
This is because all steps from A-D are important to obtain an accurate result
The SARS-Cov2 spike protein has a large N-terminal domain, a transmembrane helix and a short C-terminal region. Before the structure of the protein was known, researchers analysed its amino acid sequence using hydropathy plot analysis to predict the position of loops exposed to an aqueous environment because these show as:
A broad peak (>20 residues) of mixed positive and negative hydropathy
A broad peak (>20 residues) of positive hydropathy
A narrow (5-10 residues) of positive hydropathy
A narrow peak (5-10 residues) of negative hydropathy
Answer:
Explanation:
-g
Write electronic configuration of Na and Ca on the basis of subshell.
Na:-
Sodium has 11 electrons so the EC followed by
[tex]\\ \sf\Rrightarrow 1s^22s^22p^63s^1[/tex]
Ca:-
Calcium has 20electrons so the EC followed by
[tex]\\ \sf\Rrightarrow 1s^22s^22p^63s^23p^63d^2[/tex]
What is the oxygen tank and equipment used for and how is it used??
Answer:
Oxygen tanks are used to store gas for: medical breathing at medical facilities and at home. breathing at altitude in aviation, either in a decompression emergency, or constantly (as in unpressurized aircraft) oxygen first aid kits.
Explanation:
Mark my answer as the brainliest!
Ceramics make excellent refractory materials. A material is said to be refractory if it:
1 has high refractive index
2 retains its strength at high temperatures
3 resists the flow of electric current 4 all of the mentioned
Answer:
Option 2 is the correct answer
Explanation:
Ceramics, which mainly consist of oxides, carbides and nitrides, can withstand very high temperatures; furnaces are generally lined with such ceramics.
Iron ore is converted to iron metal in a reaction with carbon. If 1.07 moles of are used, what amount of is needed and what amounts of and , in moles, are produced
Answer:
information is missing
Explanation:
chemical equation is needed
How many atoms are in 0.100 mol of C3H8
The rate of a chemical reaction can be found by measuring how ................. the reactants are ................. or how quickly the products are ...............
The Scanning Electron Microscope, or SEM, uses beams of_______
residue from bullets or ink from a ransom note.
Electricity
Protons
Neutrons
Electrons
Answer:
Electrons.
Hope it helps.
What is the mass ratio for NH3?
Answer:
ratio by mass
14 3
mass ratio atomic mass
14/14 = 1 3/1=3
A scientist observed that tobacco plants flower only at certain times of the year. After careful consideration of this phenomenon, the scientist conducted an experiment. She grew five tobacco plants and exposed each to light for a specific period of time each day. Study the diagrams below which show the results of this experiment. Then complete the sentences that follow.
1. Since only one variable was changed in this experiment, this is called a
experiment.
2. The independent variable in this experiment is .
3. The dependent variable in this experiment is .
4. List some of the controlled variables in the experiment. (Identify at least three.)
An experiment is performed to study how the change in some variables affects other related variables.
I can't see the diagrams but I can give you general answers for each statement.
1) We define a good experiment as an experiment where only one variable is tested at the time, this is because this allows the scientists to isolate the impact of that variable in the experiment.
"Since only one variable was changed in this experiment, this is called a good experiment."
2) The independent variable is the variable that the scientists can change in an experiment, in this case, we know that she does change the hours of light that each plant gets, so we can conclude that the independent variable is the time of light exposition that each plant gets.
"The independent variable in this experiment is the time of light exposition"
3) The dependent variable in an experiment is the variable that reacts to the changes in the independent variable, it usually is the thing that the scientist wants to study. In this case, we know that she is studying the floration times of tobacco plants, so:
"The dependent variable in this experiment is the flowering time of tobacco plants"
4) Controlled variables are, in principle, independent variables, that are fixed for the whole experiment. We can't see the controlled variables because there are no graphs, but we can think about what we should fix in this type of experiment.
The temperature: All the plants should grow in the same temperature, as it can affect the flowering times.
The humidity: The humidity also could impact on the flowering of the plants, so we need to fix it for the 5 plants.
The strain: All 5 tobacco plants need to be from the same genetics, we know that different genetics from different parts of the world may react differently to changes in light or temperature, so the strains need to be equal.
Substrates: All the plants should be on the same substrate, so she can be sure that all the plants are getting exactly the same nutrients from the soil.
These are just some examples, if you were designing this experiment, you would see that there are a lot of variables that need to be controlled.
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Doping Se with P would produce a(n) ________ semiconductor with ____________ conductivity compared to pure Se.
D
Question 3
1 pts
In olden times, apothecaries used to dispense medicine using their own system of measurements
that are listed below. Use these conversions to determine how many milligrams would be in a
sample of 1.250 scruples.
1 apothecary pound = 12 ounces
1 ounce = 8 drams
3 scruples = 1 dram
1.2153 apothecary pound = 1 English pound
1 kg = 2.205 English pounds
Enter your answer to the correct number of significant digits. Do not include the units.
Changing 1.250 scruples to milligrams.
To convert from a unit to another, First write the conversion guide
then cross multiply in such a way that the unit both top and bottom
cancel out each other together with dividing or multiplying the values associated with them.
To get to the answer we have to wor it out step by step.
First step
3 scruples = 1 dram
1.250 scruples=
= [tex]\frac{1.250 scruples x 1 dram}{3scruples}[/tex] = 0.41667dram
2nd step
8 drams=1 ounce
0.41667drams =
[tex]\frac{0.41667drams x 1}{8 drams }[/tex] =0.05208 ounces
3rd step
1 apothecary pound = 12 ounces
?apothecary pound =0.05208 ounces
[tex]\frac{0.05208 ounces x 1apothecary pound }{12 ounces}[/tex] =0.00434 apothecary pound
4th step
1.2153 apothecary pound = 1 English pound
0.00434 apothecary pound =
[tex]\frac{0.00434 apothecary pound x 1 English pound}{1.2153 apothecary pound }[/tex]
==0.003571 English pound
5th step
1 kg = 2.205 English pounds
??kg =0.003571 English pound
[tex]\frac{0.003571 English pound x 1kg }{2.205 English pounds}[/tex]
=0.00161950kg
6th step
1kg =0.00161950kg
0.00161950kg=
[tex]\frac{0.00161950kg x 0.00161950kg}{1kg}[/tex]
=1,619.50mg
Therefore, 1.250 scruples=1,619.50mg
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How many centimeters are there in 5.44 meters?
Answer:
544 cm!
I hope this helped.
Answer:
The answer of your question is 544 cm
Explanation:
5.44 × 100
544 cm
Salt water has a density of 1.183g/mL. A ball has a density of 0.0134 g/mL. Will the ball float or sink?
Calculate the amount of heat required to melt 2108 g of water. The enthalpy of fusion of water is ΔHfus=6.010 kJ/mol.
since the unit for the heat of fusion is kJ/mol, you're going to have to convert the grams into moles in order to cancel out the unit. After that, you can solve like normal.
Specific heat capacity of a substance is the amount of heat required to raise the temperature by one degree Celsius of one gram of a substance. Therefore, the amount of heat required to melt 2108 g of water is 703.7kJ.
What is Enthalpy?Enthalpy term is basically used in thermodynamics to show the overall energy that a matter have. Mathematically, Enthalpy is directly proportional to specific heat capacity of a substances.
Mathematically,
q = n ×ΔH
where
q = amount of heat=?
ΔH = enthalpy=6.010 kJ/mol
n = no of moles
n = w / M.M
w = given mass
M.M = molar mass
moles of water=2108 g ÷18g/mol
=117.1 mol
substituting all the given values in the above equation, we get
q =6.010 kJ/mol ×117.1 mol
=703.7kJ
Therefore, the amount of heat required to melt 2108 g of water is 703.7kJ.
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True or False
Matter is the ability to do work or cause change.
False is the correct answer.
Answer:
False
Explanation:
It is Energy that has the ability to cause change.