Answer:
2 hydrogen
5 fluorine
1 boron
1 lithium
When doing medical research with human subjects, which four limitations are unavoidable?
Answer:
Answer
The limitations are-
1. Privacy of the individuals involved in the research process.
2. Physical and psychological risks should be minimized
3. The subjects should be chosen equitably
4. Only reasonable exposure to risks is admissible.
Explanation
The privacy of the individuals involved in the research must be taken into consideration. This will ensure safety of patient data and information. The risk of physical and physiological well being of the person must be taken into consideration in such a research. In addition to that, the subject must be made to understand every procedure and the risks involved before testing. Moreover, only minimal exposure to risks is allowed and must have been previously tested in animals to avoid deaths.
please help n let me know thank u
You have an atom with 17 protons, 18 neutrons, a net charge -1, and a mass of 35. How many electrons does this atom have?
Answer:
this atom have 18 electronsExplanation:
we know that in nutral state of atom , an atom have equal number of protons and electrons ,but in this question this atom is not nutral means it is charged this atom have -1 charge this means it gains 1 electron .in nutral state if an atom have equal number of proton and electron when the atom is charged(gain or lost certain amount of electron) number of electron become proton -the electron it losts or proton + the electron it gainsthis atom have -1 charge this means it gains 1 electron so the number of electron calculated by ; proton + the number of electron it gains; this atom have 17 protons so , number of electron =17+1=18there fore this atom have 18 electrons. I think its helpful for youA flask of water is sealed with a balloon and heated to various temperatures on a hot plate
Answer:
What is the question?
Explanation:
You just gave a statement.
Answer:
it will increase
Explanation:
Calculate the number of days after the explosion for a sample of iodine-131 to go from 100%
iodine-131 to less than 1% iodine-131. Complete chart.
It will take 56 days to go from 100% iodine-131 to less than 1% iodine-131.
From the table, we can see that the half life of iodine-131 is 8 days. We can see that it takes 8 days to have 50% of iodine-131
After 16 days, we will have 25 % of iodine-131
After 24 days, we will have 12.5 % of iodine-131
After 32 days, we will have 6.25% of iodine-131
After 40 days, we will have 3.125% of iodine-131
After 48 days, we will have 1.5625% of iodine-131
After 56 days, we will have 0.78125% of iodine-131
After 56 days, the percentage of iodine-131 drops to less than 1%.
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Is the molecule H2+ stable?
Answer: yes it is
Explanation:Bond order
The antibonding orbital is empty. Thus, H2 is a stable molecule
What happens to excess heat produced in the muscle during contraction and relaxation
Answer:
Calcium is then pumped back into the sarcoplasmic reticulum breaking the link between actin and myosin.
Explanation:
Actin and myosin return to their unbound state causing the muscle to relax. Alternatively relaxation (failure) will also occur when ATP is no longer available.
Please help me. I can’t give too much points bc I don’t have too much.
QUANTUM=
The relationship between energy and frequency=
E = hy
EN
h=
V=
Albert Einstein: PHOTONS
Pure iron, Fe , can be produced from an ore called hematite, Fe2O3 , by reaction with carbon at high temperatures. 2Fe2O3+3C⟶4Fe+3CO2 How many tons of hematite must react with carbon if an iron company needs to make 49 tons of iron?
70 tons of hematite (Fe₂O₃) is needed to produce 49 tons of iron (Fe).
We'll begin by calculating the tons of hematite (Fe₂O₃) that reacted and the tons of Fe produced from the balanced equation. This is illustrated below:
2Fe₂O₃ + 3C —> 4Fe + 3CO₂
Molar mass of Fe₂O₃ = (56×2) + (16×3) = 160 g/mol
Mass of Fe₂O₃ from the balanced equation = 2 × 160 = 320 g
Divide by 907185 to express in ton
320 / 907185 = 0.000353 ton
Molar mass of Fe = 56 g/mol
Mass of Fe from the balanced equation = 56 × 4 = 224 g
Divide by 907185 to express in ton
224 / 907185 = 0.000247 ton
SUMMARYFrom the balanced equation above,
0.000353 ton of Fe₂O₃ reacted to produce 0.000247 ton of Fe.
Finally, we shall determine the tons of hematite (Fe₂O₃) needed to produce 49 tons of Fe. This can be obtained as follow:
From the balanced equation above,
0.000353 ton of Fe₂O₃ reacted to produce 0.000247 ton of Fe.
Therefore,
X ton of Fe₂O₃ will react to produce 49 tons of Fe i.e
X ton of Fe₂O₃ = [tex]\frac{0.000353 * 49}{0.000247} \\\\[/tex]
X ton of Fe₂O₃ = 70 tons
Thus, 70 tons of hematite (Fe₂O₃) is needed to produce 49 tons of Fe.
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2.When copper (II) nitrate reacts with sodium hydroxide, copper (11) hydroxide is produced.
How many grams of copper (11) hydroxide can be prepared from 2.7 g of copper (II) nitrate
reacting with sodium hydroxide?
Answer:
2Cu + S ~~~> Cu2S Copper (C) reacts with sulfur (S) to form copper sulfide as shown in the equation. A scientist adds 12.7 grams of Cu to 3.2 grams of S to start the reaction.
Explanation:
How many molecules of carbon dioxide and how many molecules of water would be produced from 4 molecules of methane (CH4) reacting with 8 molecules of oxygen (O2)
Answer:
4
Explanation:
water would be produced from 4 molecules of methane (CH4) reacting with 8 molecules of oxygen (O2)
The products of the combustion of hydrocarbon are 4 molecules of carbon dioxide and 8 molecules of water.
What is the combustion reaction?A combustion reaction can be described as a reaction that produces fire and takes place at a high temperature. It is an exothermic reaction as well as a redox reaction that usually takes place between a fuel and mostly oxygen gas.
Examples of Combustion Reactions such as during the combustion of 4 molecules of methane reacting with 8 molecules of oxygen gas to give carbon dioxide and two molecules of water.
[tex]4CH_4 + 8O_2\longrightarrow 8H_2O + 4CO_2[/tex]
Oxygen is the essential reactant for combustion because the combustion is not possible in the absence of oxygen. Complete combustion takes place when a fuel burns completely to produce heat with oxygen and carbon dioxide.
The burning of wood fuels in the presence of air is an example of combustion. The carbon present in wood reacts with oxygen gas in the air to liberate heat and form gaseous products.
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3. Compare What is the
difference between a
chromosome and a
chromatid?
(Please answer in a simple sentence)
Answer:
A chromosome is a thread-like structure present in the nucleus that is made up of a single molecule of DNA and proteins, carrying some or all genetic materials of an organism. A chromatid is an identical half of a duplicated chromosome
Explanation:
Which substances will make a salt when combined?
Vinegar and soda
Soda and wine
Detergent and ammonia
Fertilizer and vinegar
Answer:
vinegar and soda
Explanation:
Mixing baking soda (sodium bicarbonate) and vinegar (acetic acid) causes a chemical reaction that produces a salt (sodium acetate) and water, as well as carbon dioxide gas.
Answer:
Fertilizer and vinegar
Explanation:
Fertilizer is a base, and vinegar is an acid. Salt is made when you combine a base and an acid. Plus, I got a 100% on the test and this was my answer.
which of the following is not true for chemical change
Answer:
"They can be reversed by physical changes."
Explanation:
A chemical change can form a new substance, can be detected by the change in color and they have properties different from their starting materials.
what is the resonance structure of ch3
Answer:
For the CH3- structure use the periodic table to find the total number of valence electrons for the CH3- molecule. Once we know how many valence electrons there are in CH3- we can distribute them around the central atom with the goal of filling the outer shells of each atom.
In the Lewis structure of CH3- structure there are a total of 14 valence electrons.
Also note that you should put the CH3- Lewis structure in brackets with as 1- on the outside to show that it is an ion with a negative one charge.
----- Steps to Write Lewis Structure for compounds like CH3- -----
1. Find the total valence electrons for the CH3- molecule.
2. Put the least electronegative atom in the center. Note: Hydrogen (H) always goes outside.
3. Put two electrons between atoms to form a chemical bond.
4. Complete octets on outside atoms.
5. If central atom does not have an octet, move electrons from outer atoms to form double or triple bonds.
Lewis Structures, also called Electron Dot Structures, are important to learn because they help us understand how atoms and electrons are arranged in a molecule. This can help us determine the molecular geometry, how the molecule might react with other molecules, and some of the physical properties of the molecule (like boiling point and surface tension).
Explanation:
CH3CNO can be represented by at least three different but valid Lewis structures called resonance forms, or resonance structures, shown below.
According to the periodic table, which two elements have an atomic mass less than twice their atomic number?
Answer:
Hydrogen and oxygen
Explanation:
Hydrogen
2 × atomic number = 2
atomic mass = 1.008 amu
Oxygen
2 × atomic number = 16
atomic mass = 15.999 amu
A 3.90 L sealed vessel under vacuum is filled with 6.40 g of fluorine gas. What is the pressure (in kPa) of the vessel at 25.0 ⁰C ?
From the ideal gas law, the pressure of the gas is 106 kPa.
First we must obtain the number of moles of the gas;
Number of moles = mass/molar mass
Molar mass of fluorine gas = 38 g/mol
Number of moles of F2 = 6.40 g/38 g/mol = 0.168 moles
Using the ideal gas equation;
PV = nRT
P = ?
V = 3.90 L
n = 0.168 moles
T = 25.0 ⁰C + 273 = 296 K
R = 8.314 kPa L K-1 mol-1
Substituting values;
P = nRT/V
P = 0.168 moles × 8.314 kPa L K-1 mol-1 × 296 K/3.90 L
P = 106 kPa
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The pressure of the vessel at a temperature of 25 °C is 106.73 KPa
We'll begin by calculating the number of mole of fluorine gas. This can be obtained as follow:
Mass of F₂ = 6.40 g
Molar mass of F₂ = 19 × 2 = 38 g/mol
Mole of F₂ =?Mole = mass / molar mass
Mole of F₂ = 6.40 / 38
Mole of F₂ = 0.168 moleFinally, we shall determine the pressure. This can be obtained as follow:
Volume (V) = 3.90 L
Temperature (T) = 25.0 °C = 25 + 273 = 298 K
Mole of F₂ (n) = 0.168 mole
Gas constant (R) = 8.314 L.KPa/Kmol
Pressure (P) =?PV = nRT
P × 3.9 = 0.168 × 8.314 × 298
P × 3.9 = 416.232096
Divide both side by 3.90
P = 416.232096 / 3.90
P = 106.73 KPaTherefore, the pressure of the vessel is 106.73 KPa
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which among the materials have a varying amount of components are they compounds or mixtures
Answer:
Matter can be broken down into two Zalo categories: pure substances and mixtures. Pure substances are further broken down into elements and compounds. Mixtures are physically combined structures that can be separated into their original components.
what is the difference between exergonic and exothermic reactions?
Answer:
An exergonic reaction is a type of chemical reaction that releases free energy to the surroundings. The final state of this reaction is less than its initial state. ... “Exothermic” literally means “outside heating” while “exergonic” literally means “outside work.”
Explanation:
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Which is not a type of nuclear decay?
A. Zeta
B. Gamma
C. Alpha
D. Beta
Answer:
The answer is Zeta
Explanation:
The three types of nuclear decay are Gamma, Beta, and Alpha.
1. What is the shape of an organic molecule containing a triple bond with respect to the carbons on either side of the bond?
Explain your answer
Answer:
The alkyne is linear
Explanation:
Any molecule with a triple bond is considered an alkyne. In regards to the shape, because carbon can only bond to 4 different atoms at once a triple bond fills in 3 of the required 4 atoms needed to reach the molecules ground state (when it's most stable). The more electrons shared between atoms, the shorter the bond will be which results in a stronger and more linear line. Keep in mind a quadruple bond is not possible between carbons as of now.
Why is the periodic table not arranged by atomic weight and instead arranged by atomic number?
At before Duberinor,Mendeleev tried to use atomic weight but they failed .
How do you prepare a demi-glace?
Answer:
Explanation:
sory i dont know
helpppppppppppppppppppppp
Answer:
The process in which plants release water through their leaves back into the air
Explanation
Answer:
The process in which plants release water through their leaves back into the air.
Hope this helps!
The temperature at which a solid melts is the same as the temperature at which its liquid form solidifies (true or false)
Answer:
True I think so
Explanation:
I have asked question in my profile please tell me the answer
5. Calculate the mass percent of carbon in C3H8
Answer: How to calculate the mass percent by using these instructions
1.The molar mass is the mass of a given chemical element or chemical compound (g) divided by the amount of substance (mol).
2.The molar mass of a compound can be calculated by adding the standard atomic masses (in g/mol) of the constituent atoms.
Explanation:
PLEASE EXPLAIN I KNOW THE ANSWER I NEED AN EXPLAINATION
The potential energy as a function of internuclear distance for three diatomic molecules, X2, Y2, and Z2, is shown in the graph above. Based on the data in the graph, which of the following
From the graph shown, Y2 = N2, X2 = O2, Z2 = H2.
When atoms of elements are at a large distance from each other, the potential energy of the system is high. However, as the atoms approach each other, the potential energy of the system decreases steadily. The closer the atoms come to each other, the lower the potential energy. This implies that potential energy is proportional to bond length.
Since N2 has a shorter bond length and higher energy, Y2 must be N2. The bond energy of hydrogen is small hence H2 must be X2. The bond energy of a double bond is intermediate between that of a single and triple bond hence Z2 must be O2.
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Can water molecules form ions by
themselves?
When two atoms bond chemically it is because of the interaction between
A) the nuclei of each atom.
B) the protons in each atoms.
C) all electrons in the atoms.
D) the valence electrons in each atom.
Answer:
C
Explanation:
It depends on the bonding for an explanation.
If one atom is a metal and one is a non metal it will be ionic. This is because one atom transfers its electron to the other atom giving them both a charge. They will then be bonded due to opposite forces of attraction.
If both atoms are non metals it will be covalent. Electrons pair together in the center of two atoms that have merged together and they share their electrons.
(Makes more sense with diagrams)
Using the standardized NaOH solution in the previous
question, the titration of 5.00 mL of vinegar required
42.25 mL of NaOH. What is the % of acetic acid in the
vinegar? Previous standardized NaOH solution = 0.098
Answer: Using the standardized NaOH solution in the previous question, the titration of 5.00 mL of vinegar required 42.25 mL of NaOH. What is the % of acetic acid in the vinegar? Concentration of NaOH from previous question= 0.0986 M. David C.
Explanation:
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The percentage of acetic acid in vinegar is 4.988 %., When the titration of 5.00 mL of vinegar required 42.25 mL of NaOH.
What is titration?Titration is defined as the process of chemical analysis method in which the amount of a sample's constituent is determined by mixing a precisely measured amount of the desired constituent with another material in a precise, known proportion. The equivalence point, or the point at which chemically equivalent amounts of the reactants have been combined, is to be detected by the titration.
According to the titration principle, V1=the volume of acetic acid and V1S1=V2S2
S1 is the acetic acid's strength
V1 = 42.25 ml * 0.0986 M / 5 ml = 0.833 M where V2 = Volume of NaOH S2 = Strength of NaOH
Hence, 1000 ml Vinegar contains 0.833 moles of acetic acid per 100 ml of vinegar (0.0833*60). G=4.998 grams of acetic acid
The amount of acetic acid in vinegar is 4.988%.
Thus, the percentage of acetic acid in vinegar is 4.988 %., When the titration of 5.00 mL of vinegar required 42.25 mL of NaOH.
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