Answer: element symbol: Eu. Element Atomic Number: 63.
Europium
Europium (Eu), chemical element, a rare-earth metal of the lanthanide series of the periodic table.
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Someone who is good in chemistry please help.
Answer:
2.0×10⁻⁶ mol
Prefix = (2)
exponent = (-6)
Explanation:
Given data:
Number of molecules of water = 1.23×10¹⁸ molecules
Number of moles of water = ?
Solution:
Avogadro number:
The given problem will solve by using Avogadro number.
It is the number of atoms , ions and molecules in one gram atom of element, one gram molecules of compound and one gram ions of a substance. The number 6.022 × 10²³ is called Avogadro number.
1 mole = 6.022 × 10²³ molecules of water
1.23×10¹⁸ molecules × 1 mol / 6.022 × 10²³ molecules
0.20×10⁻⁵ mol
2.0×10⁻⁶ mol
Prefix = (2)
exponent = (-6)
ellis measured the mass of five samples of quartz. his results were 39.75 g, 38.91 g, 37.66 g, 39.75 g, and 39.55 g. what was the mean mass of the samples? (p. 37
The mean mass of the given sample is 39.12g
The mean is the average of the values in the given set. It indicates that values in a particular data set are distributed equally.mass of first sample = 39.75g
mass of second sample = 38.91g
mass of third sample = 37.66g
mass of fourth sample = 39.75g
mass of fifth sample= 39.55g
Total mass of the sample = 39.75 g + 38.91 g+ 37.66 +39.75 g + 39.55 g = 195.62 g
Number of samples = 5
MEAN = SUM OF MASS OF GIVEN SAMPLES / TOTAL NUMBER OF SAMPLE= 195.62/5= 39.12gTherefore mean mass of the samples = 39.12g
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The process of fermentation involves chemical reactions that convert solid glucose (C6H12O6) into aqueous ethanol and carbon dioxide gas. Suggest how the speed of reaction alters as the temperature changes from 60C to 30C.
Explanation:
The glucose molecules changes as following:
C6H12O6 —> C2H5OH + CO2
There are 12 atoms of H on the left side and 6 atoms of the right side. It can be balance by putting 2 in front of C2H5OH as shown below:
C6H12O6 —> 2C2H5OH + CO2
There are 6 atoms of C on the left side and 5 atoms on the right side. It can be balance by putting 2 in front of CO2 as shown below:
C6H12O6 —> 2C2H5OH + 2CO2
Balance the equation with the correct coefficients. 2 3 4 5
(KCIO3-------> ( )KCI+( )O2
Answer:
2(KCLO3) - - - - > (2)KCL + (3)O3
Explanation:
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Solve these problems remember significant figures
Answer:
56) 5,722 mL
57) 750 meters
58) 88 km/hr
59) 88 km/? (I can't give you a complete answer if there's no other unit)
60) 5,169g
61) 53.1m/sec
Explanation:
When you are doing sig figs you do its operations normally. However the way you round depes on the operation;
When you are adding or subtracting sig figs you round to the least number of decimal places. In the case where there is no decimal place keep it the same
When you are multiplying or diving sig figs you round to the least amount of sig figs
The work is in the picture
which two terms describe how waves of dim blue light are different from wave of bright red light
Answer:
A, D
Lower amplitude and Shorter wavelength.
Explanation:
The blue light is having higher frequency and lower wavelength than red light. Red light is the longest wave. Hence, the two terms for blue light compared to red is lower amplitude and shorter wavelength.
What is wavelength ?Wavelength of an electromagnetic wave is the distance between its two consecutive crest or troughs. The wavelength of a wave is inversely proportional to the frequency of the wave.
Frequency of a wave is the number of wave cycles per unit time. As the frequency of the wave increases, its energy increases. Increment in energy generates higher amplitude waves.
However, the dim light has lower amplitude. Higher amplitude make the light brighter. Violet - blue region are shorter wavelength and towards red, wavelength increases.
Therefore, the dim blue light has shorter wavelength and lower amplitude than bright red light.
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If the length of a cube is 2.5 cm, the width is 2.5 cm, the height is 2.5 cm and the mass of the
cube is 157 grams. What is the density of the cube? Round answer to the nearest tenth.
2 points
Al + HCI—_AICI:
+_H2
Synthesis
Decomposition
Single Replacement
Double Replacement
Combustion
Which metal cations form a white precipitate with both H2SO4(aq) and Na2S2O4(aq)? 1. Ba2+ 2. Sr2+ 3. Fe2+ 4. Cu2+
it can be more than 1
Answer:
1. Ba2+ 2. Sr2+
Explanation:
When a solution contains the Barium ,Ba²⁺ ion or Strontium, Sr²⁺ ion, they reacts with either H₂SO₄(aq) or Na₂SO₄(aq) to produce a white precipitate of BaSO₄(s) and SrSO₄(s) respectively
The chemical reactions are given below
Ba²⁺ + H₂SO₄(aq) ⇒ BaSO₄(s) + 2H⁺ (aq)
Ba²⁺ + Na₂SO₄(aq) ⇒ BaSO₄(s) + 2Na⁺ (aq)
Sr²⁺ + H₂SO₄(aq) ⇒ SrSO₄(s) + 2H⁺ (aq)
Sr²⁺ + Na₂SO₄(aq) ⇒ SrSO₄(s) + 2Na⁺ (aq)
Determine the number of protons, neutrons and electrons in isotopes written in general format and hyphen notation.
The number of protons defines an element. If you know the element, you automatically know the number of protons. The number of protons is the same as the atomic number. A list or periodic table of the elements sorted by atomic number will tell you the number of protons. Example Every oxygen atom has 8 protons.
The number of electrons equals the number of protons in the atom unless it is ionized. The number of electrons is usually considered equal to the number of protons. The number of neutrons depends on the element. These variations in neutron number are called isotopes of the element. Adding the number of protons and the number of neutrons gives the atomic mass. Atomic weights are usually given as numbers following the hyphen after the element name. Example: Oxygen-18. Atomic weights may appear in superscripts before element symbols. Ex 18O. To get the number of neutrons, simply subtract the number of protons from the atomic mass.
Oxygen 17 is oxygen so it has 8 protons and if it is uncharged it probably has 8 choices and 17–8 = 9 neutrons. Similarly, oxygen 18 has 8 protons, 8 electrons and 10 neutrons.
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What happens when a wave hits an object?
A) the wave is reflected
B) the wave continues on
C) the wave is interfered with
D) the wave stops
Answer:
C) the wave is interfered with
How many valence electrons does antimony have
to measure out a volume of liquid, start by choosing the appropriate graduated cylinder and moving the bumper to the
To measure out a volume of liquid, start by choosing the appropriate graduated cylinder and moving the ____ Bumper__ to the top ___of the graduated cylinder to protect it from breakage. Then, pour the liquid into the graduated cylinder until the__ bottom___ of the meniscus aligns with the desired volume marking when you look at the graduated cylinder from ___eye level___
Bumper to the top, until the bottom aligns, look from eye level
To measure out a volume of liquid, start by choosing the appropriate graduated cylinder and moving the bumper to the Bumper to the top of the graduated cylinder to protect it from breakage. Then, pour the liquid into the graduated cylinder until the untill the bottom aligns of the meniscus aligns with the desired volume marking when you look at the graduated cylinder from look from eye level
What is Volume of liquid ?A liquid, solid, or gas's volume is the amount of three-dimensional space it occupies. Although there are many additional units that can be used to indicate volume, the most used ones are litres, cubic metres, gallons, millilitres, teaspoons, and ounces.
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Complete Question
To measure out a volume of liquid, start by choosing the appropriate graduated cylinder and moving the bumper to the ___ of the graduated cylinder to protect it from breakage. Then, pour the liquid into the graduated cylinder until the ___ of the meniscus aligns with the desired volume marking when you look at the graduated cylinder from ____.
I need help with this please! and thank you. if you don't know, don't comment please.
Answer:
S4O5
Explanation:
In your own words, please write a paragraph explaining what chemical and physical properties of elements mean.
Answer:
If this anwser helped you mark it the brainest please
Explanation:
Properties are features, qualities or characteristics of an item. Properties shall be used to classify the components. Properties are the attributes of a material that separates it from another substance. These properties are called physical properties and chemical properties in chemistry.
ammonia gas is used as refrigerant 0.474 atm. Pressure is required to change 2000 cm3 sample of ammonia initially at 1.0 atm to 4.22 dm3 at constant temperature. Show this data in boyles law
Answer: The pressure required is 0.474 atm
Explanation:
Boyle's Law: This law states that pressure is inversely proportional to the volume of the gas at constant temperature and number of moles.
[tex]P\propto \frac{1}V}[/tex] (At constant temperature and number of moles)
The equation is,
[tex]{P_1V_1}={P_2V_2}[/tex]
where,
[tex]P_1[/tex] = initial pressure of gas = 1.0 atm
[tex]P_2[/tex] = final pressure of gas = ?
[tex]V_1[/tex] = initial volume of gas = [tex]2000cm^3[/tex]
[tex]V_2[/tex] = final volume of gas = [tex]4.22dm^3=4220cm^3[/tex] ([tex]1dm^3=1000cm^3)[/tex]
Now put all the given values in the above equation, we get:
[tex]{1.0\times 2000}={P_2\times 4200}[/tex]
[tex]P_2=0.474atm[/tex]
The pressure required is 0.474 atm
example of a man-made object that has been changed by weathering
Answer: A man-made object that has been changed by weathering is the pyramids. The pyramids in Egypt have weathered slowly because of the dryness of the desert, but they have indeed weathered throughout the years.
6 Apply fill in the genotypes and phenotypes of the
parents and offspring in this Punnett square. Sketch
the resulting offspring possibilities in the white boxes
below. (Hint: Assume complete dominance.)
Key:
R Round pea
Genotype:
Phenotype:
allele
r Wrinkled
pea allele
R
O
O
R
Genotype:
Phenotype:
Genotype:
Phenotype:
Genotype:
Phenotype:
O
mis on :3
Genotype:
Phenotype:
Genotype:
Phenotype:
In Philip’s French class, the students are learning how to pronounce closed vowels and open vowels. The students are most likely studying French __________. A. syntax B. phonemes C. semantics D. morphemes
Answer:
It sounds like they are studying French phonemes
Explanations:
I just learned this.
The students were most likely studying French phonemes.
Words are distinguished from each other by respective sounds of the vowels in the word. There are open vowels and there are closed vowels. These exist in every language.
The part of language learning that has to do with the differentiation of pronunciation of sounds is called phonemes. This means that the students were most likely studying French phonemes.
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which element will chemically combine with fluorine to form a salt?
a. carbon
b. lithium
c. neon
d. oxygen
(Bonus) What is the most likely charge for a strontium (Sr, #38) ion? (1 pt)
*
1 point
-1
+1
-2
+2
-3
+3
+2 is the most likely charge for a strontium.
What is a charge?Charge often refers to electric charge in chemistry and physics, which is a conserved feature of some subatomic particles that governs their electromagnetic interaction.
An electromagnetic field exerts a force on matter as a result of the physical attribute of charge.
A strontium cation, a divalent metal cation, and a monoatomic dictation are all parts of strontium(2+). It plays the part of a cofactor.
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An atom is determine to have 17 protons, 18 electrons, and 18 neutrons. What are the mass number and charge of this atom or ion
Answer:
Mass # = Protons + Neutrons= 35
The charge is -1 because 17 protons arent equal to the 18 electrons each has a -1 charge
Explanation:
How many molecules are in 1 mole of nitrogen sulfide
Answer:
46.07
Explanation:
im not 100 sure this is right almost tho
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What mass of hydrogen peroxide is produced when 1. 46 g of barium peroxide react with 30. 0 ml of nitric acid solution that contains 0. 0754 g of the acid per ml?
When 1. 46 g of barium peroxide reacts with 30. 0 ml of nitric acid solution that contains 0. 0754 g of the acid per ml, the mass of the hydrogen peroxide it will produce is 0.293 g.
If the nitric acid solution contains 0.0754g of the acid per ml. then 30 ml of this contains a mass of:
mass of nitric acid = (0.0754g acid/ml) x 30 ml
mass of nitric acid = 2.262 g
Determine the number of moles of each reactant.
barium peroxide : moles = mass/MM = 1.46g/169.33 g/mol = 8.622216973 x 10-3
nitric acid : moles = mass/MM = 2.262g/63.01 g/mol = 0.03589906364
The reaction of barium peroxide with nitric acid follows the balanced chemical reaction below:
BaO2 + 2(HNO3) = H2O2 + Ba(NO3)2
1 mole of Barium peroxide reacts with 2 moles of nitric acid will produce 1 mole of hydrogen peroxide and 1 mole barium nitrate.
Using the stoichiometry, or the relationship between the amounts of substances that are involved in the chemical reaction, we can determine how much hydrogen peroxide will be produced.
If there is 8.622216973 x 10-3 moles barium peroxide, then it needs twice as much nitric acid.
moles nitric acid = 2(8.622216973 x 10-3)
moles of nitric acid = 0.01724443395
Since the amount of nitric acid we have for the reaction is greater than the calculated moles of nitric acid needed, all the barium peroxide will be used.
moles of nitric acid needed < moles of nitric acid we have
0.01724443395 < 0.03589906364
Since the barium peroxide is the limiting reagent, we will use its amount as reference.
8.622216973 x 10-3 moles barium peroxide
reacts with
0.01724443395 moles nitric acid
will produce
8.622216973 x 10-3 moles hydrogen peroxide
and
8.622216973 x 10-3 moles barium nitrate
To solve for the mass of the hydrogen peroxide, multiply its amount to its molar mass.
mass of hydrogen peroxide = 8.622216973 x 10-3 mol(34.0147g/mol)
mass of hydrogen peroxide = 0.2932821237 g
mass of hydrogen peroxide = 0.293 g
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When mercury oxide is heated, it decomposes into mercury and oxygen. If 28. 4 g of mercury oxide decomposes, producing 2. 0 g of oxygen, what is the percent by mass of mercury in mercury oxide?.
In mercuric oxide percent by mass of mercury is 93 %.
The mercuric oxide molecular formula is HgO. When mercury is reacted with oxygen, then it forms the product mercuric oxide. Mercuric oxide has a molecular mass of 216 g/mol. It has a melting point of 500°C.
The balance equation for the reaction of decomposition of mercury oxide into mercury and oxygen is,
[tex]2HgO (s)→ 2Hg (l) + O _{2}(g)[/tex]
Mass of mercury oxide = 28.4 g
Mass of the oxygen = 2 g
In mercuric oxide percent by mass of mercury is,
[tex]Mass ℅= \frac{Mass \: of \: Mercury }{Mass \: of \: Mercury \: oxide} \times 100[/tex]
[tex]= \frac{28.4 - 2}{28.4} \times 100[/tex]
= 93 %
Therefore, in mercuric oxide percent by mass of mercury is 93 %.
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Functionally, the endocrine system is like what other human body system, in that it sends information throughout the body?
A: muscular system
B: skeletal system
C: digestive system
D: nervous system
Answer:
Nervous System
Explanation:
They work together
What happens to most of the radiant energy that is not converted to thermal energy?
a. It is used in photosynthesis.
b. It is reflected into space.
c. It is converted to electricity.
d. none of the above
Q 1: Fill in the blanks:-
1. Matter is made up of small_________
2. The forces of attraction between the particles are _______ in solids, ______ in liquids and _________ in gases.
3. __________ is the change of gaseous state directly to solid state without going through liquid state, and vice-versa.
4. Evaporation causes __________
5. Latent heat of fusion is the amount of heat energy required to change 1 kg of solid into liquid at its ________
6. Solid, liquid and gas are called the three _______ of matter
7. The smell of perfume gradually spreads across a room due to ______
8. Rapid evaporation depends on the ______ area exposed to atmosphere
9. As the temperature of a system increases, the pressure of the gases ______
10. As the volume of a specific amount of gas decreases, it’s pressure _______
11. Gas molecules at higher temperatures have more _______ than at cooler temperatures.
12. Usually the total charge of a plasma is _______
13. The pressure inside of a sealed tube if you raise the temperature go ______
14. Forces of attraction in liquids are _______ than in solid
15. Liquids that move quickly downhill are described as having _____
16. A mixture contains more than ______ substance mixed in ______ proportion.
17. A solution is defined as a mixture that is----------
18. We can remove salts from a solution by using the process of ----------
19. A pure substance has a fixed__________ or ______ at constant temperature.
20. An element is made up of only one kind of _________.
21. Miscible liquids are separated by ________
22. Immiscible liquids are separated by using a _______
23. Alloy is a _______
24. Sublimation of camphor is a _________ change.
25. Most common chemical change we observe in our routine life is rusting of______.
Answer:
i think there should be some options
what is the formula of nitrous acid
Answer:
HNO2
Explanation:
It is a pale blue solution and it is only known in solution and gas form.
can mercury turn on a light?
Answer:
Mercury is useful in lighting because it contributes to the bulbs' efficient operation and life expectancy. Fluorescent and other mercury-added bulbs are generally more energy efficient and last longer than incandescent and other equivalent forms of lighting.
Explanation: