Answer:
4
4, because when there is no number after decimal then all the numbers are considered significant even 0 is the last number.
What are the various ways in which an atom of an element can achieve the noble gas configuration ?
Answer:
Atoms attain noble gas configuration by obtaining or donating and sharing of electrons present in their outermost shell.what type of solids conduct electricity in water: ionic, covalent, metallic?
Answer:
Ionic compounds are crystalline solids, soluble in water and conduct electricity when molten or in solution. These characteristics are due to the type of link that holds them together.
Figure 1 (Use this figure to answer questions 6,7, and 8. Assume that the height at point
A and point C are the same)
С
B
As the car moves from point A, to point B, and finally to point C, the total energy of the car
decreases from point A to point B, then increases from point B to point
increases from point A to point B, then decreases from point B to point
O is lost between points B and C
stays the same, but is converted between potential and kinetic energy
Answer:
JWBVH
Explanation:
NWSBWHSBHS
Which of these is made up of smallest particles of rocks which contain decayed matter of plants and animals? A. Land B. Soil C. Mineral D. Sub-soil
Answer:B. as a mineral is a deposit of fine materials it would not contain decayed materials without outside assistance
Which type of biomacromolecule contains paired bases? A. Nucleic Acid B. Carbohydrate C. Lipid D. Protein
Answer:
D.Protien
Explanation:
DNA has four nucleobases: adenine, thymine, guanine, and cytosine. The nucleobases in a DNA strand have preferred partners to form hydrogen bonds with. Cytosine pairs with guanine, and adenine pairs with thymine. These are the base pairing rules that allow DNA replication and protein synthesis to happen.
PLEASE HELP!
this is due tomorrow and i really need help!!! this is for my final grade! thank you
Answer:
what the--
Explanation:
pls tell one by one
Sodium is less reactive than potassium.
Answer:
Sodium atoms due to being smaller in size have high ionization energy and thus, it can't lose electrons easily and is more stable and less reactive. ... Hence, from this it is clear that sodium is less reactive than potassium.
Explanation:
The equilibrium constant (K) for the reaction
2HCI(g) = H2(g) + Cl2(g)
is 4.17 x 10-34 at 25°C. What is the equilibrium constant for the reverse reaction at the same
temperature?
H2(g) + Cl2(g) = 2HCl(g)
Answer: The equilibrium constant for the reverse reaction at the same temperature is [tex]2.40 \times 10^{33}[/tex].
Explanation:
The given reaction equation is as follows.
[tex]2HCl(g) \rightleftharpoons H_{2}(g) + Cl_{2}(g)[/tex] ... (1)
It's equilibrium constant (K) value is [tex]4.17 \times 10^{-34}[/tex].
Also, another reaction equation is as follows.
[tex]H_{2}(g) + Cl_{2}(g) \rightleftharpoons 2HCl(g)[/tex]
This is the reverse of equation (1). Hence, its equilibrium value is calculated as follows.
[tex]K' = \frac{1}{K}\\= \frac{1}{4.17 \times 10^{-34}}\\= 2.40 \times 10^{33}[/tex]
Thus, we can conclude that the equilibrium constant for the reverse reaction at the same temperature is [tex]2.40 \times 10^{33}[/tex].
What is the wavelength of light with 4.01 x 10^-19 J of energy? (The speed of light in a vacuum is 3.00 x 10^8 m/s, and Planck's constant is 6.626 x 10^-34 Jos.)
A. 1820 nm
B. 496 nm
C. 202 nm
D. 551 nm
Answer:
D
hope it helps:)))!!!!!!
The concept Planck's quantum theory of radiation is used here to determine the wavelength of the light. The wavelength of the light with 4.01 x 10⁻¹⁹ J of energy is 496 nm . The correct option is B.
What is Planck's quantum theory?According to Planck's quantum theory, different atoms and molecules can emit or absorb energy in discrete amount only. The smallest amount of energy which can be emitted or absorbed in the form of electromagnetic radiation is called quantum.
The energy of the radiation absorbed or emitted is directly proportional to the frequency of the radiation. It is given by the equation:
E = hν
ν = E / h
4.01 x 10⁻¹⁹ J / 6.626 x 10⁻³⁴ = 6.05 × 10¹⁴ Hz
We have,
ν = c / λ
λ = c / ν
3.00 x 10⁸ / 6.05 × 10¹⁴ = 4.958 × 10⁻⁷ m
1 nm = 1 × 10⁻⁹ m
4.958 × 10⁻⁷ m = 495.8 nm = 496 nm
Thus the correct option is B.
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An electron in a hydrogen atom moves from level 1 to level 4. The electron then drops from level 4 to level 2. Which
statement describes the most likely result?
O The energy absorbed in the first move equals the energy released in the second move.
O The energy absorbed in the first move is greater than the energy released in the second move.
O The energy released in the first move equals the energy absorbed in the second move.
O The energy released in the first move is greater than the energy absorbed in the second move.
Answer:
B
Explanation:
When the electron goes up levels it absorbs energy to enter that higher energy state. When it goes down, it releases energy but just not as much because 1-4 is more than 4-2.
The reactants of two chemical equations are listed.
Equation 1: CuSO4 and NaOH
Equation 2: Fe and CuSO4
Based on the type of reaction, which reaction can be used to extract copper metal from copper sulfate solution?
A - Equation 2, because Fe being more reactive, replaces Cu from CuSO4
B - Equation 2, because Fe being more reactive, replaces S from CuSO4
C - Equation 1, because Na being more reactive, exchanges position with Cu in CuSO4
D - Equation 1, because Na being more reactive, exchanges position with S in CuSO4
The reaction that can be used to extract copper metal from copper sulfate solution would be equation 2.
Fe will displace Cu from CuSO4 because it is more reactive. In other words, Fe ranks higher than Cu in the reactivity series.
Thus: [tex]Fe + CuSO_4 ---> Cu + FeSO_4[/tex]
Even though Na will displace Cu from CuSO4, equation 1 will result in the formation of Cu(OH)2 instead of free Cu because it is a double replacement reaction.
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Identify the substance which has same number of molecules in 14g N2
a) 3.4g NH3
b) 15g NO
c)64g O2
d) 32g SO2
e)1g H2
2 moléculas de clorato de potasio (KClO3) forman 2 moléculas de cloruro de potasio (KCl) y 3 moléculas de oxígeno (O2
The complete question is as follows: 2 molecules of potassium chlorate (KClO3) form 2 molecules of potassium chloride (KCl) and 3 molecules of oxygen (O2). Write a balanced equation for this reaction?
Answer: The balanced chemical equation is [tex]2KClO_{3} \rightarrow 2KCl + 3O_{2}[/tex].
Explanation:
A balanced equation is defined as the equation which contains same number of atoms on both reactant and product side when a chemical reaction occurs.
Hence, when 2 molecules of potassium chlorate [tex](KClO_{3})[/tex] form 2 molecules of potassium chloride (KCl) and 3 molecules of oxygen [tex](O_{2})[/tex] then its balanced equation will be as follows.
[tex]2KClO_{3} \rightarrow 2KCl + 3O_{2}[/tex]
Here, number of atoms on the reactant side as as follows.
K = 2Cl = 2O = 6Number of atoms on the product side are as follows.
K = 2Cl = 2O = 6Since, the number of atoms on reactant side are equal to the number of atoms on product side. So, this reaction equation is balanced.
Thus, we can conclude that the balanced chemical equation is [tex]2KClO_{3} \rightarrow 2KCl + 3O_{2}[/tex].
In vascular plants, the absorption of water from the soil into root hairs depends principally upon the presence of a
A. phototropic response by the root hairs
B. geotropic response by the conducting tissue
OOOO
C. higher concentration of water in the soil than in the root hairs
D. higher concentration of water in the root hairs than in the soil
Answer:
the answer is C) higher concentration of water in the soil than in the root hairs
Explanation:
Answer:
the answer is c
Explanation:
i just got it
17) A 0.20 M solution of HCl with a volume of 15.0 mL is exactly neutralized by the 0.10 M solution of NaOH with what volume? HINT: Use the titration formula from table T. First multiply, then divide. o 1.5 mL O 7.5 mL 7 o 3.0 mL 0 30. mL
Answer: A 0.20 M solution of HCl with a volume of 15.0 mL is exactly neutralized by the 0.10 M solution of NaOH with 3 mL volume.
Explanation:
Given: [tex]M_{1}[/tex] = 0.20 M, [tex]V_{1}[/tex] = 15.0 mL
[tex]M_{2}[/tex] = 0.10 M, [tex]V_{2}[/tex] = ?
Formula used is as follows.
[tex]M_{1}V_{1} = M_{2}V_{2}[/tex]
Substitute the values into above formula s follows.
[tex]M_{1}V_{1} = M_{2}V_{2}\\0.20 M ]times 15.0 mL = 0.10 M ]times V_{2}\\V_{2} = 30 mL[/tex]
Thus, we can conclude that a 0.20 M solution of HCl with a volume of 15.0 mL is exactly neutralized by the 0.10 M solution of NaOH with 3 mL volume.
Complete and balance the equation for the single-displacement reaction. Phases are optional. balanced equation: 2NaBr+Cl2=2NaCl+Br2
PCl5 <-> PCl3 + Cl2
PCl5 decomposes into PCl3 and Cl2 according to the equation above. A pure sample of Pcl5 is placed in a rigid, evacuated 1.00 L container. The initial pressure of the PCl5 is 1.00 atm. The temperature is held constant until the PCl5 reaches equilibrium with its decomposition products. The figures below shows the initial and equilibrium conditions of the system.
As the reaction progresses toward equilibrium, the rate of the forward reaction
A) increases until it becomes the same as the reverse reaction rate at equilibrium
B) stays constant before and after equilibrium is reached
C) decreases to become a constant nonzero rate at equilibrium
D) decreases to become zero at equilibrium
Answer:
PCl5 <-> PCl3 + Cl2
PCl5 decomposes into PCl3 and Cl2 according to the equation above. A pure sample of Pcl5 is placed in a rigid, evacuated 1.00 L container. The initial pressure of the PCl5 is 1.00 atm. The temperature is held constant until the PCl5 reaches equilibrium with its decomposition products. The figures below show the initial and equilibrium conditions of the system.
As the reaction progresses toward equilibrium, the rate of the forward reaction
A) increases until it becomes the same as the reverse reaction rate at equilibrium
B) stays constant before and after equilibrium is reached
C) decreases to become a constant nonzero rate at equilibrium
D) decreases to become zero at equilibrium
Explanation:
At equilibrium, both forward and backward reactions take place with constant speed.
The reaction will never cease.
Due to this reason chemical equilibrium is called dynamic in nature.
At equilibrium:
the rate of forward reaction = rate of backward reaction
As the reaction progresses toward equilibrium, the rate of the forward reaction decreases to become a constant nonzero rate at equilibrium.
Answer is option C).
When a system is in a state of chemical equilibrium, neither the reactant concentration nor the product concentration changes over time, nor does the system exhibit any further changes in its attributes. Here the correct option is C.
The system reaches a condition of chemical equilibrium when the rate of the forward reaction equals the rate of the reverse reaction. The system is considered to be in a state of dynamic equilibrium when the concentrations of the reactants and products do not change further as a result of the equal rates of the forward and reverse processes.
Equilibrium is impacted by a number of variables, including temperature, pressure, and the system's concentration. Here at equilibrium the rate of the forward reaction decreases to become a constant nonzero rate at equilibrium.
Thus the correct option is C.
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A properly designed experiments changes one variable at a time. A student wanted to know which type of sugar would yield the greatest amount of energy for the cell when metabolized during cellular respiration by mitochondria. The student mixed yeasts in three different sugar solutions: maltose, glucose, sucrose. The three sets of yeasts were monitored to determine which sugar type yielded the most energy. List three factors that the student must keep constant during the experiment
Answer:
The amount of water
The amount of sugar and
The amount of yeast
Explanation:
A constant variable is that variable in an experiment which must be kept the same for all groups in order not to alter the results of the experiment.
In this question, the independent variable i.e. the variable being manipulated is the TYPE OF SUGAR USED while the dependent variable i.e. variable that responds to change is AMOUNT OF ENERGY. Three different types of sugar were used viz: maltose, glucose, and sucrose. To not alter the outcome of the experiment, the constants of this experiment i.e. variables that must be the same for all groups of the experiment, include the following:
- The amount of water
- The amount of sugar
- The amount of yeast used
A solution of ammonia NH3(aq) is at equilibrium. How would the equilibrium
change if NH4+ were added to the solution?
Answer: The equilibrium will shift in the direction of [tex]NH_3[/tex]
Explanation:
The chemical equation for the aqueous solution of ammonia follows:
[tex]NH_3+H_2O\rightleftharpoons NH_4^++OH^-[/tex]
According to Le-chtelier's principle:
If there is any change in the variables of the reaction, then the equilibrium will shift in that direction of equilibrium to minimize the effect.
If we add more amount of [tex]NH_4^+[/tex] to the solution, more of the products will be present. But according to Le-chtelier's principle, to minimize this effect, the equilibrium will shift in the backward direction that in the direction of [tex]NH_3[/tex]
Hence, the equilibrium will shift in the direction of [tex]NH_3[/tex]
where was the first oil well drilled
Answer:
First oil well in the United States, built in 1859 by Edwin L. Drake, Titusville, Pennsylvania.
What is the difference between a chemical and physical change?
Find out how many atoms will fit in one apple . Adius of an apple is about 3.5 cm and the radius of an atom is 1.5 angstrom
Answer:
1.3 × 10²⁵ atoms
Explanation:
Step 1: Calculate the volume of an apple
The radius of an apple is 3.5 cm (3.5 × 10⁻² m). If we assume it is a sphere, we can calculate its volume using the following expression.
V = 4/3 × π × r³
V(apple) = 4/3 × π × (3.5 × 10⁻² m)³ = 1.8 × 10⁻⁴ m³
Step 2: Calculate the volume of 1 atom
The radius of 1 atom is 1.5 A (1.5 × 10⁻¹⁰ m). If we assume it is a sphere, we can calculate its volume using the following expression.
V = 4/3 × π × r³
V(atom) = 4/3 × π × (1.5 × 10⁻¹⁰ m)³ = 1.4 × 10⁻²⁹ m³
Step 3: Calculate how many atoms are in 1 apple.
V(apple)/V(atom) = 1.8 × 10⁻⁴ m³/1.4 × 10⁻²⁹ m³ = 1.3 × 10²⁵
PLEASEEEE HELPPPPP!!
Answer:
Its the first one
Explanation:
4 mol is the highest of the Bunch and 4.0L is the lowest making the first answer the correct one
La siguiente reacción es altamente exotérmica: N2H4 + O2 → N2 + H2O ∆H= -622,4 Kj Cuánto calor se libera al producir 5 moles de nitrógeno.
Answer: -3112 kJ of heat will be released when 5 moles of nitrogen is produced.
Explanation:
We are given:
Moles of nitrogen = 5 moles
Given chemical reaction follows:
[tex]N_2H_4+O_2\rightarrow N_2+2H_2O;\Delta H=-622.4 KJ[/tex]
By stoichiometry of the reaction:
If 1 mole of nitrogen gas is produced, the heat released is -622.4 kJ
So, if 5 moles of nitrogen gas is produced, the heat released will be = [tex]\frac{-622.4kJ}{1mol}\times 5mol=-3112kJ[/tex]
Hence, -3112 kJ of heat will be released when 5 moles of nitrogen is produced.
When a substance freezes or condenses, which four of the following things are true for it's particles?
(Select 4 answers)
A. Lose energy
B. Gain energy
C. Move more
D. Move less
E. Become further apart
F. Become closer together
Answer:
Gain energy, move less, become closer together
Consider the balanced reaction below:
P2O3 + 3H2O → 2H3PO3
How many grams of diphosphorus trioxide, P203, are required to produce 10.2 moles of phosphorous acid, H3PO3?
Answer:
5.1 moles of P2O3 are required
Explanation:
Based on the reaction, 1 mole of diphosphorus trioxide, P2O3, reacts with 3 moles of water to produce 2 moles of phosphorous acid, H3PO3. That means the conversion factor is: 1mol P2O3 = 2mol H3PO3.
The moles of P2O3 required to produce 10.2mol H3PO3 are:
10.2mol H3PO3 * (1mol P2O3 / 2mol H3PO3) =
5.1 moles of P2O3 are requiredWrite the electronic configuration of calcium and potassium.
Answer:
Calcium= 2,8,8,2
Potassium= 2,8,8,1
Answer:
Electronic configuration of Potassium (K)Atomic number of potassium = 19
Therefore number of electrons = 19
Since, maximum number of electrons in outermost orbit will not be more than 8, thus the 19th electron of potassium atom will reside in 4th.
Thus, electronic configuration of potassium is
given in first pic.
Number of orbit in potassium = 4
Electronic configuration of Calcium (Ca)Atomic number of calcium = 20
Therefore number of electrons = 20
Thus, electronic configuration of calcium is given in sec pic.
Number of orbit in calcium = 4
Explanation:
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PLZ HELP!!! QUESTIONS ARE BELOW!!! :D PLZ COMPLETELY ANSWER THE QUESTIONS WITH A GOOD ANSWER :)
Answer: sorry its lagging i hope this help fore 18.. =D
Explanation:
n,s is repeating the cycle of the inside
Answer/Explanation:
18, a,
I believe the n, and s represents North, South, or just the way the arrows are rotating repeatedly.
18, b,
The phenomenon re-occurring shows the alignment of magnetic dipoles with in a magnet, like inside. The arrows show a direction in the line with an external magnetic field in a way that it can produce its own magnetic fields that seem to travel from North to the South.
18, c,
Incorrect. Refrigerator magnets have multiple layers of magnification, they use opposite polarities to stay this way. If he puts the magnet sideways it may stick to the fridge
~ LadyBrain
Which is made up of only one type of atom?
A.a solution
B.a homogeneous mixture
C.an element
D.a compound
Answer:
C. an element
Explanation:
Elements are pure substances and made up of only one type of atoms which cannot be further broken down.
If no loss or gain of electrons occur by mixing of two atoms, we say that they may be attached to each
other due to
A proton attraction
B neutron attraction
C sharing of electrons
D opposite charges
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Answer:
The correct option is option C
Explanation:
Loss or gain of electron(s) occurs in a type of attraction known as electrovalent or ionic attraction. In this type, there is transfer (or loss) of electron(s) from a metal atom to become positively charged while a nonmetal accepts (or gains) this electron to become negatively charged.
When this does not happen, two metal atoms can become attached by sharing the same electrons through a form of attraction known as covalent bonding. Here, the two atoms share electrons (known as shared pair) together to achieve there octet configuration on the outermost shell.