True. I am always sad but my heart is always happy cuz it knows there are good things ahead
why is calcuim (ca) in group 2. period 4 on the periodic table
Answer:
Calcium (Ca) is in group 2 and period 4 on the periodic table be because Calcium has 2 valence electrons and 4 electron shell. Thus, calcium is a metal like all other group 2 element.
Explanation:
EXPLAIN BRIEFLY WHY CHEMISTRY IS CONSIDERED AS MAJOR BRANCH OF SCIENCE
Answer:
Chemistry is sometimes called “the central science,” because it bridges physics with other natural sciences, such as geology and biology. Chemistry is the study of matter and its properties.
Explanation:
~found it~
Câu 15: Nguyên tử X nặng gấp 2 lần nguyên tử cacbon. Nguyên tử X đó có nguyên tử khối và
kí hiệu hóa học là
A. 24_Mg. B. 16_O C. 56_Fe D. 32_S
Answer:
A
Explanation:
Rank from most ionic to least ionic
a. WO3
b. MnS
c. MnS2
d. ZnS
e. ZrS2
The order of increasing ionic property is;
WO3 < ZrS2 < MnS2< ZnS < MnS
Ionic compounds are compounds that contain an ion pair. Typically, ionic compounds are formed between metals and nonmetals.
The degree of ionic character depends on the type of metal involved and the magnitude of charge it carries.
Typically, first row transition metals form ionic compounds. The degree of ionic character depends on the row in which the metal is found and the magnitude of charge it carries.
Hence, the order of ionic character of the compounds from most ionic to least Ionic is; WO3 < ZrS2 < MnS2< ZnS < MnS.
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A blank is formed or separated by physical processes.
How many moles are in 29.5 grams of Ax?
A. 1.3 moles
B. 1.8 moles
C. 0.78 moles
D. 678 moles
The number of moles present in 29.5 grams of argon is 0.74 mole.
The atomic mass of argon is given as;
Ar = 39.95 g/mole
The number of moles present in 29.5 grams of argon is calculated as follows;
39.95 g ------------------------------- 1 mole
29.5 g ------------------------------ ?
[tex]= \frac{29.5}{39.95} \\\\= 0.74 \ mole[/tex]
Thus, the number of moles present in 29.5 grams of argon is 0.74 mole.
"Your question seems to be missing the correct symbol for the element"
Argon = Ar
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I'll mark you the brainiest if you answer this question first!!!
Read the CDC's recommendations for frequency of handwashing. Do you agree with these recommendations? Explain your answer using the results from the experiment as evidence.
Link down below:
https://www.cdc.gov/handwashing/when-how-handwashing.html
Answer:
Yes, Because the dishes that are unwashed have the most bacteria while the soap & water dish has the least bacteria.
Explanation:
Hope this help
. The atomic number of a newly discovered element is found to be 128, and its mass number is 279.
How many protons, neutrons, and electrons are found in an ion of this element bearing a charge of
5−?
Which characteristic do valence electrons indicate about reactions between atoms? (1 point)
o electronegativity difference
o absolute electronegativity
o bond type
o bond number
The characteristic of reactions that depends on valence electrons is the bond type.
In chemistry, a chemical bond could be;
IonicCovalentThe type of bond formed depends on the number of valence electrons present. When there are few valence electrons on an atom, it mostly forms ionic bonds.
When there are more electrons on an atoms, it mostly forms covalent bonds and the electrons between the atoms are shared.
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Answer:
D: bond number
A volume of 10.0 mL of 25 mg/L Mn2+ solution was diluted to make a solution with the final volume of 50.0 mL. Calculate the concentration (in mg/L) of the final solution
Taking into account the definition of dilution, the concentration of the final solution is 5 mg/L.
First of all, you have to know that dilution is the reduction in concentration of a chemical in a solution. The process consists of adding more solvent to the same amount of solute.
In a dilution the amount of solute does not change, but as more solvent is added, the concentration of the solute decreases.
A dilution is mathematically expressed as:
Ci×Vi = Cf×Vf
where
Ci: initial concentration Vi: initial volume Cf: final concentration Vf: final volumeIn this case, you know:
Ci= 25 mg/L Vi= 10 mL Cf= ? Vf= 50 mLReplacing in the definition of dilution:
25 mg/L × 10 mL= Cf × 50 mL
Solving:
Cf= (25 mg/L × 10 mL)÷ 50 mL
Cf= 5 mg/L
In summary, the concentration of the final solution is 5 mg/L.
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1. How many MOLECULES are contained in 80.0 grams of sodium hydroxide?
Answer:
2 molecules
Explanation:
In 80 grams there will be 2 molecules of NaOH, so mass of Sodium would be 23 x 2 = 46g.
What is a polyprotic buffer?
Can anyone tell me why I got this question wrong? I have no clue.
Answer:
what queastiion
Explanation:
Answer:
what is the question
Explanation:
...
Which of the following has more atoms?
One mole of zinc
One mole of gold
One mole of silver
One mole of magnesium
O They all have the same number of atoms
Answer:
They all have the same number of atoms
Explanation:
Which of the following has more atoms?
One mole of zinc
One mole of gold
One mole of silver
One mole of magnesium contians
O They all have the same number of atomst
a mole of anything contains Avogadros number of 6.022X10^23 things
which has the greatest number of thing? a dozen eggs, a dozen cookies, a dozen pizzas?
a dozen is a number means 12
a mole is a number that that means 6.022 X 10^23 you calculate the molar mass from the chemical formula, but every j mole contains 6.022X10^23
particles.
just like every dozen contains 12
so
They all have the same number of atoms
A supermassive black hole can be found at
Location 1
Location 2
Location 3
Location 4
Answer:
location 2
Explanation:
Why would you expect the materials used to make pot holders to be poor conductors of heat?
Answer:
Pot holders are meant to protect your hand from the heat of the pot, and so it would need to be a poor conductor of heat in order to do its job correctly. Silicon dioxide is a solid at room temperature and methanol is a liquid.
A car slows to a velocity of 20 m/s and weighs 20 kg. Does the car have momentum? If so, what is the momentum of the car?
Answer:400
Explanation:
20x20
P(momentum)= mxv
Mass times velocity = momentum
On vacation, Aria went scuba diving in the Pacific Ocean for the very first time. She rose toward the surface of the water at a steady speed for 4 minutes. She rose 36 meters in that time. What was her speed? HELP ME ASAP!!!!!!!!!!!!!
Aria speed during scuba diving was 0.15 m/s.
Speed is the ratio of the distance travelled to the time taken. Speed is given by:
Speed = distance / time
Given that the distance travelled was 36 meters and the time was 4 minutes, hence:
Time = 4 minutes × 60 seconds per minute = 240 seconds
Speed = 36 m / 240 s
Speed = 0.15 m/s
Therefore Aria speed during scuba diving was 0.15 m/s.
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Please tell me an example of a protein structure that would give positive test with Molisch’s Reagent?
Answer:
positive reaction for Molisch's test is given by almost all carbohydrates (exceptions include tetroses & trioses). It can be noted that even some glycoproteins and nucleic acids give positive results for this test (since they tend to undergo hydrolysis when exposed to strong mineral acids and form monosaccharides).
Answer:
glycoproteins
Explanation:
A positive reaction for Molisch's test is given by almost all carbohydrates (exceptions include tetroses & trioses). It can be noted that even some glycoproteins and nucleic acids give positive results for this test (since they tend to undergo hydrolysis when exposed to strong mineral acids and form monosaccharides).
A student creates a sports drink by dissolving 5.0 g of powder in 250 mL of water. The green colour of the drink is due to the presence Green Dye X, which has a lambdamax of 630 nm. A calibration curve (absorbance versus concentration) at lambdamax is created for varying concentrations (mM) of Green Dye X which has the equation y = 26.4x. If 1.0 mL of the sports drink is diluted to 10. mL with water, then the absorbance is measured to be 0.450, what is the mass percent of Green Dye X in the drink powder if the molecular weight is 418.4 g mol-1?
The mass percent of Green Dye X in the drink powder if the molecular weight is 418.4 g/mol is 0.355%
Beer's law explains the relation between the concentration of a solution to its absorbance (A) by using the equation.
A = ∈×C×Lhere:
∈ = molar absorptivityL = path lengthNow from the calibration curve in the question, the plot between the absorbance and the concentration gives a straight line of y = mx.
Here
y = absorbance x = concentrationThe equation of the calibration curve is given as:
y = 26.4xi.e.
0.450 = 26.4x[tex]\mathbf{x = \dfrac{0.450}{26.4}}[/tex]x = 0.017 mMIf the sports drink was 10 times diluted while taking the absorption measurement. Then, the actual concentration of green dye in the sports drink is:
= 0.017 mM × 10
= 0.17 mM
The number of moles of green dye in 250 mL (i.e. 0.25 L) sports drink is estimated as:
= 0.17 mmol/L × 0.25 L
= 0.0425 mmol
However, the mass of the green dye present in the sports drink is
= 0.0425 mmol ×418.4 g/mol
= 17.782 mg
Finally, the mass percent of green dye in the drink powder is:
[tex]\mathbf{ = \dfrac{mass (dye)}{mass (powder)} \times 100\%}[/tex]
[tex]\mathbf{ = \dfrac{17.782 \ mg }{5.0 \ g} \times 100\%}[/tex]
[tex]\mathbf{ = \dfrac{17.782 \ mg }{5000 \ mg} \times 100\%}[/tex]
= 0.355 %
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If you have 4.01 g of H2, how many grams of NH3 can be produced?
Answer:
136.5886g of NH3
Explanation:
N2 + 3H2 = 2NH3
The mass of the N2 = 4.01
3H2 has a 2/1 ratio
This means the mass of 3H2 is twice as much as N2.
NH3= 2*N2 = 2*4.01 = 8.02 of NH3
Then, by multiplying the mass by MX (17.031)
8.02*17.031=136.5886g can be produced. Round it if needed.
What is surface tension and why is it important?
Answer:
What is surface tension?
Explanation:
Surface tension and droplets: Surface tension is responsible for the shape of liquid droplets. Although easily deformed, droplets of water tend to be pulled into a spherical shape by the cohesive forces of the surface layer.
Surface tension forces between mucosal surfaces play an important role in the pathogenesis of the disease. The obstruction of upper airway elicit the activation of autonomic nervous system, hypoxemia, and arousal from sleep.
Hope it helps
According to the law of conservation of matter, which statement about chemical reactions is true? A. Atoms cannot be created or destroyed by chemical reactions. B. Atoms are created by some reactions and destroyed by others. C. Energy is created as atoms are destroyed in chemical reactions. D. Every atom destroyed in a chemical reaction must be replaced.
find the major product
The answer is B.
Back-side attack by water at the more substituted carbon.
You can follow the steps.
Step1: Electrophilic attack forms a bromonium ion intermediates.
Step2: Back-side attack by water at the more substituted carbon opens the bromonium ion intermediates.
Step3: H2O removes a proton from the intermediates.
introduced in the 13th-16th? century from sabah in the reign of the sultanate of sulu, and became extinct on maguindanao or were transported back to sabah. Bone fragments are the only proof left behind of their existence ...ill mark u as brainliest
The Elephant Maximus is the species that was introduced and later became extinct on Maguindanao.
Extinction occurs as all members of a species die, and therefore the species disappears. This includes complete extinction or extinction of the species in a specific zone.
In the case of the Elephant Maximus, which is known as the Asian Elephant, this species became extinct in a region known as Maguindanao in the Philippines.
This partial extinction occurred as the elephants from this zone were taken to Sabah in Malaysia from the 13th century to the 16th century. This occurred because the Sultans of this region considered this elephant to be a valuable and even sacred animal.
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Fat is a ____________ (Body Buiding / Energy Giving / Protective ) food.
Fat is a energy giving , protective food
hope it helps
I give my best answer almost
help pleaseeeeeeeeeeeeeeeeeeeeeeeeeeeeee
Answer:
evaporation
Explanation:
An example of this is when puddles evaporate into the air after it has rained. Condensation is the opposite: gas → liquid
Hope this helps!
Which of the following molecules is nonpolar?
Ο Α. CO2
Ο Β. SO,
Ο Ο Ο Ο
O C. CO
D. NO
Answer:
CO2
Explanation:
There are two types of moleculesPolarNon polarNon polar molecules are insoluble in water .
Option A
[tex]\sf \longmapsto co_{2}[/tex]
[tex]\sf Co_{2}[/tex] is a non polar molecule.[tex]\sf \longmapsto\sf Co_{2}[/tex]
Lewis Structure =
[tex]\sf \longmapsto\sf \: o \: = c = o[/tex]
[tex]\sf \longmapsto4 + 6(2)[/tex]
[tex]\sf \longmapsto16[/tex]
Non polar molecules are non-soluble in water.
What is this answer to this problem
Answer:
gdhjvdhihfhddjcuh
dhsgbeyfgjgjjkk
tjfhh
gjgu
The conversion of acetyl chloride to methyl acetate occurs via the following two-step mechanism: Reaction sequence of acetyl chloride to methyl acetateAccess the text alternative for PROBLEMS Kinetics and Rate Laws 6.49. Add curved arrows to show the movement of the electrons in each step. Write the rate equation for this reaction, assuming the first step is rate-determining. If the concentration of were increased 10 times, what would happen to the rate of the reaction? If the concentrations of both and were increased 10 times, what would happen to the rate of the reaction? Classify the conversion of acetyl chloride to methyl acetate as an addition, elimination, or substitution.
If the concentration of acetyl chloride is increased ten times the rate of reaction is increased ten times.
The conversion of acetyl chloride to methyl acetate is a substitution reaction. Recall that a substitution reaction is one in which a moiety in a molecule is replaced by another.
In this reaction, the CH3O- ion replaces the chloride ion. In the first step, the CH3O- ion attacks the substrate in a slow step. This creates a tetrahedral intermediate. Loss of the chloride ion yields the methyl acetate product.
The rate determining step is the formation of the tetrahedral intermediate. Since the reaction is first order in the acetyl chloride, if its concentration is increased ten times the rate of reaction is increased ten times.
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