Answer:
Boron : B :: Beryllium :Be
Explanation:
Boron is an element found in group 13 of the periodic table. It has three electrons in its outermost shell hence a valency of 3.
Beryllium is an element in group two of the periodic table. It has a valency of two hence there are two electrons in its outermost shell.
Boron and beryllium are similar words. The symbol of boron is B while the symbol of beryllium is Be.
what does the periodic table allow chemist to do
a . organize compounds
b . develop atomic theory
c . predict properties of element
d . produce new elements
Vhon Anadome
Atomic nucleus questions
Which of the following decay processes results in the largest change in mass of a nucleus?
Choose 1 answer:
А
Beta decay
Gamma decay
Neutron emission
D
Alpha decay
Answer:
d
Explanation:
1 point
Write the equation for when aluminum oxide breaks down to yield aluminum and oxygen. What are the coefficients in this balanced equation? (Note: Be sure to
keep the reactants and products in the order that they appear in the question)
Answer:
Al + O2 ------> Al + 2O
Explanation:
hope this helps :)
A balanced equation is the representation of the elements with their symbols and coefficients. The balanced reaction for aluminum oxide is 2Al₂O₃ → 4Al + 3O₂.
What is a balance equation?A balanced equation represents the chemical elements along with their coefficients. The reactants are written on the left side while the products of the reaction are written on the right side of the arrow.
The balanced equation for decomposition reaction for aluminum oxide as,
The unbalanced equation is,
Al₂O₃ → Al + O₂
Oxygen atoms are balanced on both sides of the equation as,
2Al₂O₃ → Al + 3O₂
Now, the number of aluminum is balanced on both sides as,
2Al₂O₃ → 4Al + 3O₂
Therefore, the balanced equation is 2Al₂O₃ → 4Al + 3O₂.
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How many moles in 4.65 g of Helium?
Answer:
4.65 g x 1 mol/4.0026 g/mol = 1.162 mol helium
Explanation:
A sample of a compound contains 41.33 g of carbon and 8.67 g of hydrogen. The molar mass of the
compound is 87.18 g/mol. What is the molecular formula for the compound?
Show your steps.
Answer:
C6H15
Explanation:
First, we calculate the empirical formula as follows:
C = 41.33 g
H = 8.67 g
We convert each mass value to mole by dividing each element by its molar mass (C = 12g/mol, H = 1g/mol)
C = 41.33g ÷ 12g/mol = 3.44mol
H = 8.67g ÷ 1g/mol = 8.67mol
Next, we divide each mole value by the smallest (3.44mol)
C = 3.44mol ÷ 3.44mol = 1
H = 8.67mol ÷ 3.44mol = 2.52
We multiply this ratio by 2 to get a simple whole number ratio
C = 1 × 2 = 2
H = 2.52 × 2 = 5.04
Based on this, the whole number ratio of C and H is 2:5, hence, the empirical formula is C2H5.
The molecular mass of the compound is given as 87.18 g/mol, hence, the molecular formula is calculated as follows:
(C2H5)n = 87.18
[12(2) + 1(5)]n = 87.18
[24 + 5]n = 87.18
(29)n = 87.18
n = 87.18 ÷ 29
n = 3.006
Approximately to whole number, n = 3
Hence, the molecular formula of the compound is [C2H5]3
= C6H15
Name two types of silk
Answer:
Tussar silk
Charmeuse
Explanation:
Hope this helps! :)
Witch part of an atom is mostly empty space?
Which of the following represents an element ? H2O H2 NaCl CaCO3
Answer:
H₂
Explanation:
H₂ is hydrogen in its elemental form.
H₂O, NaCl, and CaCO₃ are all examples of elements added together to create compounds.
Please help!!!!!!!!!!!!!!!!!!!
Answer:
Hydrochloric acid + calcium hydroxide = calcium chloride + water
What is S for silicon tetrachloride, SiCl4
S denotes the ''number of shared electron pairs by an atom'', Hence, Silicon shares its 4 electrons with 4 Cl-atoms. Thus the Value of S is 4 in SiCl₄ .It is also known as covalency
What is Covalency ?
The number of covalent bonds that a particular atom can make with other atoms in forming a molecule.
Covalent bond id formed by the sharing of electron between two atoms.
Hence, Silicon shares its 4 electrons with 4 Cl-atoms. Thus the Value of S is 4 in SiCl₄ . It is also known as covalency
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Please somone help me with a chemistry question brainliest to whoever answers correctly and 20 points
Answer:
342.15 g/mol
..........
Can someone help me
Answer:the second largest one
Explanation:
both weels are pushing at it
Which prefix indicates a molecule with 2 carbon atoms?
O A. Eth-
O B. Oct-
O c. Hex-
O D. Meth-
The answer is A.Eth-
The prefix indicates a molecule with 2 carbon atoms is eth- and the correct option is option A.
What is IUPAC Nomenclature?
The IUPAC system of nomenclature is a set of logical rules framed which are mainly aimed at giving an unambiguous name to an organic compound.
IUPAC stands for International Union of Pure and Applied Chemistry
A prefix to the name comes before the molecule. The prefix of the molecule's name is based on the number of carbon atoms.
For example, a chain of six carbon atoms would be named using the prefix hex-.
The suffix to the name is an ending that is applied that describes the types of chemical bonds in the molecule.
Therefore, The prefix indicates a molecule with 2 carbon atoms is eth- and the correct option is option A.
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Can you guys help!!!
During a certain chemical reaction, the temperature gradually increases.
Which statement best describes this process?
A. It is combustion.
B. It is endothermic.
C. It is a closed system.
D. It is exothermic.
No links!!!
No spams!!
Answer:
D. lt is exothermic is the correct ans
Aqueous solutions of a strong acid and a weak acid of equal concentrations are compared. Which of the following statements are true?
I. The strong acid reacts with a metal oxide but the weak acid does not
II. The weak acid is less disassociated than the strong acid
III. The strong acid has a greater conductivity that the weak acid.
Answer:
Explanation:
How much pressure should an airbag have?
Answer:
It should have about 70-80 pounds of air pressure.
Answer:
5 lbs is what I read on the internetluv </3
Which atom attracts electrons most strongly? br F Rb
Fluorine has the highest electronegativity in comparison to other elements therefore, the F atom attracts electrons most strongly.
What is electronegativity?The electronegativity of an atom measures the tendency of an element to attract the bonded electrons pairs towards itself. The electronegativity of an atom is determined with respect to another bonded atom.
Electronegativity can be described as a chemical property of an atom or a functional group to attract electrons toward itself. The electronegativity of an atom depends on the atomic number and the distance of valence electrons from the charged nuclei.
When two different atoms are bonded through a bond. More electronegative will attract the electron density of the bond towards itself.
As we know, the electronegativity decreases as we move down the group in the periodic table. Fluorine is the most electronegative element in the periodic table therefore, Fluorine (F) will attract the electrons toward it most strongly.
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A test light with an electrical resistance of 9.00 S2 draws a current of 1.50 A when
it is connected to an electrical source. How much power does the light use?
Answer:
20.25 W
Explanation:
Applying,
P = I²R.................... Equation 1
Where P = Power, I = current drawn by the test light, R = Resistance of the test light
From the question,
Given: I = 1.5 A, R = 9.00 Ω
Substitute these values into equation 1
P = (1.5²)(9)
P = 2.25×9
P = 20.25 W
How would the balloons interaction with each other change if the balloons were moved further apart? Explain.
Explanation:
It is known that like charges repel each other and unlike charges attract each other.
As the balloons are facing each other with like charges so they will repel each other. Hence, they will move apart.
But when balloons were moved further apart then interaction between them will decrease and then there will be no force of repulsion or force of attraction.
can u pls answer 22, 23, 24
Answer:
I'm terribly sorry but the download is not working for me! All it says is Download pdf, and when I click it, It does nothing except for refreshing the page!
Explanation:
Find the area of the sector with a central angel of 120 and a radius of 8 inshces. Leave in terms of pie
Answer:
A = 66.98 square in.
Explanation:
The Area of a sector is given by the formula
[tex]A = \frac{\theta}{360}\times \pi r^2[/tex]
here θ is the central angle and r is the radius
given that θ = 120° and radius = 8 inches
[tex]A = \frac{120}{360}\times3.14\times 8^2[/tex]
A = 66.98 square in.
(02.01 MC) Which state of matter does this model represent?
O Solid
O Liquid
O Gas
O Plasma
Answer:
Hello There!!
Explanation:
I believe the answer is O Gas.
hope this helps,have a great day!!
~Pinky~
Write a nuclear equation for the beta decay of Promethium-165
Answer:
see your answer in pic
Explanation:
There can be emissions of radiations like gamma radiation. There can be emission of particles too like alpha particle. Therefore, the nuclear equation for the beta decay of Promethium-165 is
¹⁶⁵Pm[tex]\rightarrow[/tex]⁰e₋₁ + ₆₂Sm¹⁶⁵
What is nuclear decay?Nuclear decay is process in which the radioactive element releases particles or radiations. Alpha particles is ⁴₂He. Alpha particle is nothing but helium particle. The kinetics that is related to nuclear decay is of first order.
The nuclear equation for the beta decay of Promethium-165 is
¹⁶⁵Pm[tex]\rightarrow[/tex]⁰e₋₁ + ₆₂Sm¹⁶⁵
Beta decay of Promethium-165 is the emission of electron particle from the given isotope. the product is Samarium ₆₂Sm¹⁶⁵.
Therefore, the nuclear equation for the beta decay of Promethium-165 is
¹⁶⁵Pm[tex]\rightarrow[/tex]⁰e₋₁ + ₆₂Sm¹⁶⁵
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What is the pH of a solution whose H + concentration is 4.0 10 –9?
Answer:
he pH of a solution is defined as the negative log10 [H+] ... 1 x 10-11. 11. Acidic Solution. 1 x 10-4. 4. 1 x 10-10. 10. 1 x 10-5. 5. 1 x 10-9.
Explanation:
m
Which of the following are equal to 32°F?
A. 0°C
B. 273 K
C. 100°C
D. 373 K
Answer:
A. 0°C............... sorry, the anwser has to be 20 characters long
Determine the volume of a helium balloon given the balloon was filled from a container 0.15L of gas at 2 atm if the new pressure is 0.97 atm. Assume constant temperature.
Answer:
The volume of the helium balloon is 0.306 L.
Explanation:
Boyle's law states that the volume occupied by a given gaseous mass at constant temperature is inversely proportional to pressure. That is, if the pressure increases, the volume decreases, while if the pressure decreases, the volume increases.
Mathematically, Boyle's law indicates that the product of pressure and volume always has the same value:
P*V= k
Assuming that you have a certain volume of gas V1 that is at a pressure P1 at the beginning, by varying the volume of gas to a new value V2, then the pressure will change to P2, and it will be fulfilled:
P1*V1= P2*V2
In this case:
P1= 2 atmV1= 0.15 LP2= 0.97 atmV2= ?Replacing:
2 atm* 0.15 L= 0.97 atm* V2
Solving:
[tex]V2= \frac{2 atm* 0.15 L}{0.97 atm}[/tex]
V2= 0.306 L
The volume of the helium balloon is 0.306 L.
Part of Newtons first law states an object at rest stays at rest unless acted upon by an unbalanced force. Which one is NOT an example of this law?
Solution :
Sir Isaac Newton was a great scientist. The discoveries of the Newton change the way we see the world. Newton gave us the fundamental principles through which the entire universe is governed.
Newtons 1st law of motion states that a body moves or stays in position until and unless an external force is applied to the body.
This is the law of nature.
An example which do not support this law can be a body having a huge mass and a small boy applies force to move it but is unable to move the body.
1. BaBr2(aq) + H2SO4(aq) →?
please balance the equation and predict the products
Answer:
BaBr2 (aq) + H2SO4 (aq) → BaSO4 (s) + 2 HBr (aq)
Explanation:
This is a precipitation reaction: BaSO4 is the formed precipitate.
If the half life of iridium-182 is 15 years, how much of a 3 gram sample is left after 2 half-lives?
A) .57 grams
B) .70 grams
C) 2.25 grams
D) .75 grams
Answer:
D. 0.75 grams
Explanation:
The data given on the iridium 182 are;
The half life of the iridium 182, [tex]t_{(1/2)}[/tex] = 15 years
The mass of the sample of iridium, N₀ = 3 grams
The amount left, N(t) after two half lives is given as follows;
[tex]N(t) = N_0 \left (\dfrac{1}{2} \right )^{\dfrac{t}{t_{1/2}} }[/tex]
For two half lives, t = 2 × [tex]t_{(1/2)}[/tex]
∴ t = 2 × 15 = 30
[tex]\dfrac{t}{t_{(1/2)}} = \dfrac{30}{15} = 2[/tex]
[tex]\therefore N(t) = 3 \times\left (\dfrac{1}{2} \right )^2 = 0.75[/tex]
∴ The amount left, N(t) = 0.75 grams
HELP ASSAP!!
The molecule shown is an example of a
A)
methyl ester.
B)
wax.
C)
triglyceride.
D)
sodium carboxylate.
Answer: b
Explanation:
The molecule is WAX.
What is WAX?Waxes consist of long-chain fatty acid attached through ester oxygen to long-chain alcohol. These molecules exist completely water-insoluble and typically solid at biological temperatures.
The main objective of the waxes is to provide a water-proof layer to the feathers, but other processes have also been suggested. Some of these lipids can also recreate a role as pheromones in sexual signaling.
the characteristics of wax are-
1. Solid at room temperature; liquid at more increased temperatures.
2. Primarily hydrocarbon in design.
3. Water repellent; insoluble in water.
4. Smooth texture; buffable under slight pressure.
5. Low toxicity; low reactivity.
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