Answer:
Mass = 142.25 g
Explanation:
Given data:
Mass of Ca(OH)₂ = ?
Number of moles of Ca(OH)₂ = 1.92 mol
Solution:
Formula:
Mass = number of moles × molar mass
Molar mass of Ca(OH)₂ = 74.09 g/mol
by putting values,
Mass = 1.92 mol × 74.09 g/mol
Mass = 142.25 g
Gather data: Four other pairs of elements in the same chemical family are listed below. List the number of valence electrons in each element. Beryllium Nitrogen Oxygen Fluorine Magnesium Phosphorus Sulfur Chlorine
Explanation:
Valence electrons is the number of electrons in the outermost shell of an atom. For the main group elements, the group number represents the number of valence electrons.
Beryllium
This belongs to the group 2 hence, it has valency of 2.
Nitrogen
This belongs to group 5, hence it has valency of 5.
Oxygen
This belongs to group 6, hence it has valency of 6.
Fluorine
This belongs to group 7, hence it has valency of 7.
Magnesium
This belongs to group 2, hence it has valency of 2.
Phosphorus
This belongs to group 5, hence it has valency of 5
Sulphur
This belongs to group 6, it has valency of 6
Chlorine
This belongs to group 7, it has valency of 7
Answer:
Beryllium: 2 valence electrons.
Nitrogen: 5 valence electrons.
Oxygen: 6 valence electrons.
Fluorine : 7 valence electrons.
Magnesium : 2 valence electrons.
Phosphorus : 5 valence electrons.
Sulphur : 6 valence electrons.
Chlorine : 7 valence electrons.
Which element is more electronegative, Ge or Bi
Answer:
Ge is more electronegative
Explanation:
Riboflavin is one of the B vitamins It is also known as B6 and is made up of carbon, hydrogen, nitrogen and oxygen atoms. When 10.0 g of vitamin B6 is burned in oxygen, 19.88 g of CO2 and 4.79 g of H2O are obtained. Another experiment shows that vitamin B6 is made up of 14.89% of N. What is the simplest formula for vitamin B6
Answer:
C₁₇H₂₀N₄O₆
Explanation:
First, we need to determine the percentage of the atoms in the molecule. Then, assuming a basis of 100 we must convert the mass of each atom to moles. Simplest formula is the simplest ratio of atoms presents in the molecule:
%C:
19.88g CO2 * (12.01g/mol C / 44.01g/mol CO2) = 5.425g C
5.425g C / 10.0g * 100 = 54.25% C
%H:
4.79g H2O * (2*1.01g/mol / 18.015g/mol) = 0.537g H
0.537g H / 10.0g * 100 = 5.37%
%N:
14.89%
%O:
100 - 14.89% - 54.25% - 5.37% = 25.49%
Moles of each atom in a basis of 100g:
C: 54.25g * (1mol / 12.01g) = 4.517moles
H: 5.37g * (1mol / 1.01g) = 5.317 moles
N: 14.89g * (1mol / 14.01g) = 1.063 moles
O: 25.49g * (1mol / 16g) = 1.593 moles
Dividing each amount of moles in the lower number of moles (moles N):
C = 4.517mol / 1.063mol = 4.25
H = 5.317mol / 1.063mol = 5
N = 1.063mol / 1.063mol = 1
O = 1.593mol / 1.063mol = 1.5
This ratio multiplied 4 times to obtain whole-numbers:
C = 4.25*4 = 17
H = 5*4 = 20
N = 1*4 = 4
O = 1.5*4 = 6
The simplest formula for vitamin B6 is:
C₁₇H₂₀N₄O₆HELLOSOEOODORODODODORRLKRKLRLRLF
Answer:
I'd say maybe Dangerous? I hope this helps
Answer:
golden is sometimes referred to as shiny and beatitful
Explanation:
How many formula units are contained in 0.57 g Cao?
Which of the following chemical equations correctly
represents between calcium hydroxide and
hydrochloric acid?
+ 2HCI →
CaCl2(aq) + 2H20)
'(aq)
+ HCI →
'(aq)
A Ca(OH)2(aq)
B Ca(OH)2(aq)
C Ca(OH)2(aq)
D Ca(OH)2(aq)
O
caCl(aq)
CaCl2(aq)
+ H2O
+ 2H200
+ HCl(aq)
+ 2HCI
'(aq)
Caci,
2(aq)
+ 2H211)
+
2(g)
Answer:
Ca(OH)2 + HCI
Explanation:
Calcium hydroxides formula is: Ca(OH)2
Hydrochloric Acids formula is : HCI
Please rate and give thanks!
Question 2 of 10 A chemist has a block of copper metal (density is 8.96 g/mL). They drop the metal into a graduated cylinder containing water, and find the volume change is 2.90 mL. What is the mass of the block, in grams? h
Answer:
m = 25.98 g
Explanation:
Given data:
Density of copper metal = 8.96 g/mL
Volume of copper metal block = 2.90 mL
Mass of copper metal block = ?
Solution:
The volume of given block of copper is equal to the volume change of water by adding this block.
Density formula:
d = m/v
by putting values,
8.96 g/mL = m/ 2.90 mL
m = 8.96 g/mL × 2.90 mL
m = 25.98 g
How does changing the number of electrons in an atom affect the atom?
A purified protein is in a HEPES buffer at pH 7.0 with 600 mM NaCl. A 1 mL sample of the protein solution is dialyzed against 1.0 L of the same HEPES buffer with 0 mM NaCl. Once the dialysis has come to equilibrium, what is the concentration (in mM) of NaCl in the protein sample
Answer:
Explanation:
Using the dilution formula to determine the final concentration of NaCl in the protein sample.
[tex]M_1V_1 = M_2V_2[/tex]
[tex]600 \ mM \times 1 \ mL= M_2 \times ( 1000\ mL + 1 \ mL)[/tex]
[tex]M_2= \dfrac{600 \ mM \times 1 \ mL}{ ( 1001\ mL)}[/tex]
[tex]M_2= 0.599 \ mM[/tex]
However, when dialysis attains equilibrium, it implies that the sample was dialyzed twice, SO:
[tex]M_2 = \dfrac{600 \ mM\times 1 \ mL}{201 \ mL} = 2.97 \ mM[/tex]
Now, take the concentration as 2.97 mM
Then:
[tex]M_f = \dfrac{2.985 mM \times 1 mL}{201 \ mL}[/tex]
[tex]M_f = 0.01485 \ mM[/tex]
[NaCl] = 0.01485 mM
Which of these has the most kinetic energy?
A. a 25 kg fish tank sitting on a table
B. a .05 g fish swimming in a fish tank
C. a 7,500 kg car parked on a steep hill
D. a 50 kg boulder suspended from a cliff
Which energy transformation occurs when you rub your hands together to warm them?
kinetic energy to radiant energy
thermal energy to kinetic energy
thermal energy to potential energy
want energy to thermal energy
Explanation:
The answer is thermal energy/ kinetic energy.. because friction on hands promotes thermal energy. because you want your hands 2 be warm, rubbing them 2gether creates heat and absorption of heat thru the skin which skin is susceptible to warm, humans can put hands under arm pits to warm hands, without any available heat source..
4.Calculate the Hydroxide, Hydrogen ion and POH of solution if the PH of solution is 7.b
5.Solution A Has PH =4 and solution B has PH = 7.How many times greater is the Hydroxide ion
concentration in solution A than the Hydronium ion concentration in solution B
the ph is gonna be your value and the 4 is gonna be your main subject
so as the ph is your value u gonna ad your ph and 7 and 4 toghter then multiple your answer 2 times because ph represent multiple and your value
1. All the following are correctly balanced except -
A. 2C2H2 + 502 4CO2 + 2H20
B. 4Fe + 302 – 2Fe2O3
C. NaHCO3 Na2CO3 + H2O + CO2
D. 2CH,OH + 302 2C02 + 4H20
= 1
= 2
5
= 3
10
= 6
7
8
Write a balanced half-reaction for the reduction of gaseous oxygen (02) to liquid water
to liquid water (H2O) in acidic aqueous solution. Be sure to add physical state symbols
where appropriate.
a
A balanced half-reaction :
O₂(g)+ 4H⁺(aq)+ 4e⁻⇒2H₂O(l)
Further explanationGiven
Reduction of gaseous oxygen (O₂) to liquid water(H₂O)
Required
A balanced half-reaction
Solution
Step 1 : Equalize the number of elements by adding coefficients
Equates element O
O₂(g)⇒2H₂O(l)
Step 2 : Equalize H by adding H⁺ on the opposite side (the deficient area of H).
O₂(g)+ 4H⁺(aq)⇒2H₂O(l)
Step 3 : Equalized the charge using the addition of electrons (e⁻) along the H⁺ field.
O₂(g)+ 4H⁺(aq)+ 4e⁻⇒2H₂O(l)
Does the model represent a chemical reaction? (Image)
Answer:
yes it is a chemical reaction
Explanation:
because the substances combined and made something new
Which element in group 17 has the highest ionization energy
Answer:
fluorine
Explanation:
it has the highest electronegativity in the group and in the periodic table
Why is it sometimes not practical to use scale models when representing objects in space?
well space base stars and I'm done know
Explanation:
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Sometimes making a scale model is not practical because it is expensive and takes a lot time to build up for large models of objects. Rebuilding of destroyed scale models is very difficult.
What is scale model ?A physical model that is geometrically comparable to an item is called a scale model . Scale models may be larger than small prototypes like anatomical structures or subatomic particles, but they are often smaller than huge prototypes like cars, buildings, or people.
Mockups are models created at the same scale as the prototype. In addition to being used as toys, scale models are also utilized as tools for engineering design and testing, marketing, and sales, as well as for military strategy and special effects in movies.
The pursuit of model construction as a pastime for artistic purposes is also common. However, it is very expensive and time consuming to create a scale model.
Find more on scale models:
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an organic pesticide was decomposed by an oxygen combustion procedure to convert the chlorine in the molecule to water soluble chloride the chloride was then precipitated as AgCl A 0.7715 gram precipitate was obtained from 500 grams of pesticide Calculate the percentage chlorine in the pesticide
Answer:
0.0382%
Explanation:
Given that:
Silver chloride = AgCl
Molar mass of AgCl = (107.87 + 35.5) = 143.37 g/mol
Chlorine, Cl = 35.5
143.37g/mol of AgCl = 35.5 g of Cl
Hence, 1 g AgCl will give ; (35.5 / 143.37)
1g AgCl = 0.2476 g Cl
In 0.7715 g AgCl, ; (0.2476*0.7715) g Cl
= 0.1910 g Cl
Therefore, percentage of Cl in 500g sample:
(Mass of Chlorine / mass of sample) * 100%
(0.1910 / 500) * 100%
0.000382 * 100%
= 0.0382%
The columns in the periodic table are called groups. What do the elements in group 17 have in common?
Answer:
All of the elements in group 17 all have 7 valence electrons. This is one thing they all share in common.
Explanation:
A molecule or ion that donates the hydrogen in a hydrogen bond is a hydrogen bond donor A molecule or ion that binds to this hydrogen is a hydrogen bond acceptor. Specify the hydrogen bonding behavior of the 4 species below by selecting: donor for species that act as donors only acceptor for species that act as acceptors only both for species that act as both donors and acceptors neither for species that act neither as donors nor as acceptors.
The question is incomplete, the complete question is found in the image attached.
Answer:
1- acceptor
2-donor
3-acceptor
4-donor
Explanation:
A hydrogen bond acceptor is a molecule that has an electronegative atom having a lone pair of electrons that participates in the hydrogen bond.
A hydrogen bond donor is the molecule that supplies the hydrogen atom of a hydrogen bond.
If we look at structure I-IV in the image attached, I and III are hydrogen bond acceptors because they all possess electronegative atoms having lone pairs of electrons but do not have hydrgen atoms bonded to highly electronegative atoms.
Similarly, structures II and IV are hydrogen bond donors. The C=C double bond is electron withdrawing and highly electronegative making the hydrogen atoms attached to it acidic and hydrogen bond donors. Also, nitrogen is an electronegative atom thereby making structure IV a hydrogen bond donor.
How many moles of hydrogen react with 4.5 moles of oxygen to synthesize water?
Answer:
9moles of hydrogen gas
Explanation:
To solve this problem, we write the reaction expression first;
2H₂ + O₂ → 2H₂O
We have been given the number of moles of oxygen gas to be:
Number of moles of oxygen gas = 4.5moles
From the balanced reaction expression:
1 mole of oxygen gas reacts with 2 moles of hydrogen gas
4.5moles of oxygen gas will react with 4.5 x 2 = 9moles of hydrogen gas
Please help ASAP
Read thing for the question thanks!!
Answer:
JOSHUA
Explanation:
JOSHUA
How many significant figures are in 3.20x10^2 g?
Answer:
3
Explanation:
For numbers with decimals, count the number after the decimal.
7. You are about to perform some intricate electrical studies on single skeletal muscle fibers from a gastronemius muscle. But first, you must prepare 6L of a 170 mM NaCl solution in which to bath the isolated muscle during your studies. How many grams of NaCl must you weigh out on the lab balance to prepare this bath solution
Answer:
58.61 grams
Explanation:
Taking The molecular weight of NaCl = 58.44 grams/mole
Determine how many grams of NaCl to prepare the bath solution
first we will calculate the moles of NaCl that is contained in 6L of 170 mM of NaCI solution
= ( 6 * 170 ) / 1000
= 1020 / 1000 = 1.020 moles
next
determine how many grams of NaCl
= moles of NaCl * molar mass of NaCl
= 1.020 * 58.44
= 58.61 grams
An scientist located a nugget of an unknown substance. However, he determined that this nugget has a
mass of 63 g and a volume of 9 cm^3. What is the density of this nugget?
Answer: The density of this nugget is [tex]7\text{ g cm}^{-3}[/tex] .
Explanation:
We are given that,
Mass of nugget = 63 g
Volume = [tex]9\ cm^3[/tex]
The computation of density of a substance is given by :-
[tex]\text{Density}=\dfrac{\text{Mass}}{\text{Volume}}\\\\\Rightarrow\ \text{Density}=\dfrac{63}{9}\text{ g cm}^{-3}[/tex]
[tex]\Rightarrow\ \text{Density =}7\text{ g cm}^{-3}[/tex]
Therefore, the density of this nugget is [tex]7\text{ g cm}^{-3}[/tex] .
Cleavage refers to the way a rock:
A. shine
B. breaks
C. streaks
D. is made
Explanation:
Türküm ben yanlisikla siteye girdim.
Answer:
breaks
Explanation:
I think its braks
A force of 100 newtons was necessary to lift a tree. A total of 50 joules of work was done. How far was the tree lifted
Answer:
Distance lift the tree = 0.5 m
Explanation:
Given:
Work done = 50 joules
Force = 100 newton
Find:
Distance lift the tree
Computation:
Distance = Work done / Force
Distance = 50 / 100
Distance = 0.5 m
Distance lift the tree = 0.5 m
Atoms of arsenic (As) are often added to silicon (Si) in a process called doping to change the conductivity of the silicon. How does the addition of arsenic change the conductivity of silicon?
a) An atom of arsenic has one fewer valence electron and more electron shells than an atom of silicon, so the conductivity decreases because the arsenic atom gains an electron.
b) An atom of arsenic has one more valence electron and more electron shells than an atom of silicon, so the conductivity decreases because the arsenic atom loses the electron.
c) An atom of arsenic has one fewer valence electron and fewer electron shells than an atom of silicon, so the conductivity increases because the arsenic atom gains an electron.
d) An atom of arsenic has one more valence electron and more electron shells than an atom of silicon, so the conductivity increases because the arsenic atom loses the electron.
HAD TO POST THIS THIS BC THE OTHER POSTED IS WRONG
Answer:
d) An atom of arsenic has one more valence electron and more electron shells than an atom of silicon, so the conductivity increases because the arsenic atom loses the electron.
Explanation:
This is an example of a n-type semiconductor. The additional electron introduced to the 'grid' of silicon atoms causes an increase in the conductivity of the silicon. This additional electron is introduced as arsenic loses its extra electron.
Answer:
D is the answer, the other one is wrong.
Explanation:
a A student decreases the temperature of a 484 cm ^ 3 balloon from 570 K to 285 Assuming constant pressure, what should the new volume of the balloon be? Round your answer to one decimal place.
Answer:
242 cm³.
Explanation:
The following data were obtained from the question:
Initial volume (V₁) = 484 cm³
Initial temperature (T₁) = 570 K
Final temperature (T₂) = 285 K
Pressure = constant
Final volume (V₂) =?
The new volume (i.e final volume) of the balloon can be obtained by using the Charles' law equation as illustrated below:
V₁/T₁ = V₂/T₂
484 / 570 = V₂ / 285
Cross
484 × 285 = 570 × V₂
137940 = 570 × V₂
Divide both side by 570
V₂ = 137940 / 570
V₂ = 242 cm³
Therefore, the new volume of the balloon is 242 cm³
How many molecules are in 15 moles of CO2?
There are 90.345 x 10^23 molecules in 15 moles of CO2.
What is Avogadro's number?Avogadro's number is the number of units, atoms or molecules in one mole of a substance which is equals to 6.02214076 × 1023. This number is also known as the Avogadro constant.
This means that one mole of a substance is equals to 6.02214076 × 1023 atoms, ions or molecules then 15 moles is equals to 90.345 x 10^23 molecules so we can conclude that there are 90.345 x 10^23 molecules are in 15 moles of CO2.
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