Answer:
21. Most metals are brittle.
22. increases from top to bottom within the group
23. Neon is the most stable element because its highest occupied energy level is filled.
24. transfer of electrons
25. electrons are not shared equally between atoms
26. BeCl2
27. double-replacement and decomposition
28. exothermic
29. The reaction rate decreases.
30. The salt dissolved most quickly in the warm water.
31. saturated
32. feels slippery
33. hydroxide ions in solution
34. stay about the same
35-40. I do not know.
41. a bee hovering around a bee hive
42. the number of valence electrons in atoms of the element
Explanation:
21. Metals are ductile and malleable (conveniently also characteristics for chewing gum). They are stretchy and squishy. Brittle is the opposite of stretchy and squishy, and is a characteristic of non-metals.
22. On the periodic table, elements higher up are safer to use in labs. They are safer because they are less likely to react with other substances. Therefore the tendency to react with other substances increases from top to bottom within the group.
23. "Noble gases stable" (periodic table song by ASAP Science). Neon is a noble gas, therefore it is stable. When elements have only one electron to gain or lose, they are very reactive or least stable.
24. The formation of an ionic bond (metal + non-metal) is caused by the giving and receiving of electrons. Neutrons and protons do not transfer. Electrons are shared in covalent/molecular bonds (between non-metals).
25. A polar covalent bond occurs between non-metals, therefore they share electrons (ionic bonds transfer electrons). Non-metals become anions (whereas metals become cations). Polar bonds have unequal sharing and nonpolar bonds have equal sharing.
26. A one-to-two ratio of beryllium ions to chloride ions means for every Be, there are two Cl. The number of atoms is represented by the ratio, and the numbers of atoms are written as subscripts after the element symbol.
27. MgCO2 reacting with HNO3 to form magnesium nitrate and carbonic acid is a double-replacement reaction. The elements in the beginning substances "switch partners" to form the products.
Carbonic acid then breaks down into water and carbon dioxide is decomposition. This occurs when the elements that make up a compound are split up.
28. In 2Cu + O2 => 2CuO + 315 kJ , the energy is on the right side. The right side is the products, or the stuff that was made. kJ is a unit to measure energy, therefore energy was made. Exothermic is the term that means energy was released.
29. Since oxygen is needed for a fire to burn, decreasing the oxygen slows the reaction rate (the reaction is burning, formally known as combustion).
30. Two things help substances dissolve: heat and stirring. Warm water is hotter than room-temperature water and ice water. This makes the salt dissolve faster.
31. A solution that contains more solute than it would normally hold is saturated. Saturated means there is a more than concentrated amount of solute in the solution. Concentrated is when there is a maximum amount of solute that will dissolve.
32. Acids do not feel slippery -- that is a characteristic of a base. To remember, bases are generally soaps and soaps are slippery. Acids taste sour and bases taste bitter. Both acids and bases change the color of an indicator .
33. A base produces hydroxide ions, represented by OH. The OH is usually at the end of the chemical formula. Acids produce hydrogen ions, generally written at the front of the chemical formula.
34. Adding a little bit of acid to a buffer will cause the pH of the solution to stay about the same, probably increase a little. Buffer solutions are meant to make the pH "buffer". To remember, DVDs used to buffer. It's the same thing as "lag" for phones.
35-40: I'm sorry, I have no answer.
41. Electrons orbit like the plants revolve around the sun. Electrons revolve around a nucleus. A bee hovering around a bee hive is probably flying around it in circles.
42. The tendency of an element to react is closely related to the number of valence electrons in atoms of the element. If the valency is 8, the electron shell is full. The element is stable, opposite to reactive -- this applies to all noble gases (group 8A on the periodic table). If the valency is 1 or 7, the element is very close to being stable but not, the "desire" is so great and makes the element very reactive.
what is the mass in grams of 1.9×1023 atoms of lead?
Answer:
Explanation:
# moles that exist in 1.9 X 10 23 =
= # of atoms/# of Avogadro 's num
= 1.9 X 10 23 / 6.02x10 23
= 0.266 mole of Pb
now we calculate the mass
mass of lead = # mol x m.wt
= 0.266 X 106.4
= 28.30 gram
Chromium(III) oxide reacts with hydrogen sulfide (H2S) gas to form chromium(III) sulfide and water: Cr2O3(s) + 3H2S(g) → Cr2S3(s) + 3H2O(l) To produce 156 g of Cr2S3, (a) how many moles of Cr2O3 are required? mol (b) how many grams of Cr2O3 are required? g
Answer:
(a) 0.779 mol Cr₂O₃
(b) 118 g Cr₂O₃
Explanation:
Step 1: Convert 156 g Cr₂S₃ to moles
Cr Molar Mass - 52.00 g/mol × 2 = 104.00 g/mol
S Molar Mass - 32.07 g/mol × 3 = 96.21 g/mol
156 g Cr₂S₃ ÷ 200.21 g/mol = 0.779182 mol Cr₂S₃
Step 2: Find conversion from Cr₂S₃ to Cr₂O₃
1 mol Cr₂S₃ equals 1 mol Cr₂O₃
Step 3: Use Dimensional Analysis
0.779182 mol Cr₂S₃ · [tex]\frac{1 \hspace{2} mol \hspace{2} Cr_2O_3}{1 \hspace{2} mol \hspace{2} Cr_2S_3}[/tex] = 0.779182 mol Cr₂O₃
0.779182 mol Cr₂O₃ ≈ 0.779 mol Cr₂O₃ (3 significant figures)
Step 4: Convert moles to grams
Cr Molar Mass - 52.00 g/mol × 2 = 104.00 g/mol
O Molar Mass - 16.00 g/mol × 3 = 48.00 g/mol
0.779182 mol Cr₂O₃ · 152.00 g/mol = 118.436 g Cr₂O₃
118.436 g Cr₂O₃ ≈ 118 g Cr₂O₃ (3 significant figures)
Enzymes which are usually increase the rate of a reaction by________.
Is it possible for a diprotic acid to have Ka1?
Answer:
Yes, it is possible.
Explanation:
A diprotic acid is an acid that can release two protons. That's why it is called diprotic.
Monoprotic → Release one proton, for example Formic acid HCOOH
Triprotic → Releases three protons, for example H₃PO₄
Polyprotic → Release many protons, for example EDTA
it is a weak acid.
In the first equilibrum, it release proton, and the second is released in the second equilibrium. So the first equilibrium will have a Ka1
H₂A + H₂O ⇄ H₃O⁺ + HA⁻ Ka₁
HA⁻ + H₂O ⇄ H₃O⁺ + A⁻² Ka₂
The HA⁻ will work as an amphoterous because, it can be a base or an acid, according to this:
HA⁻ + H₂O ⇄ H₃O⁺ + A⁻² Ka₂
HA⁻ + H₂O ⇄ OH⁻ + H₂A Kb₂
How can pH go high over time
Factors that raise pH in a swimming pool. 1. Natural pH Rise: Carbon Dioxide Loss. The chemistry of pH sounds a lot more complicated than it is. In short, the less CO 2 in solution, the ... 2. Sanitizers and their pH Impact. 3. pH and alkalinity adjustment chemicals.
(0.0046 x 15000.0) + (2817 x 13)
Answer:
36690
Explanation:
What does 3.5 degree of unsaturation tell you?
Answer:
It means the chemical entity is a radical
Explanation:
When we talk of unsaturation, we are referring to the number of pi-bonds in a chemical entity. The alkane, alkene and alkyne organic family are used to as common examples to explain the term unsaturation.
While alkynes have 3 bonds, it must be understood that they have 2 pi bonds only and as such their degree of saturation is two.
In the case of an alkene, there is only one single pi bond and as such the degree of unsaturation is 1.
Now in this case, we have a fractional 0.5 degree of unsaturation alongside the 3 to make a total of 3.5. So what’s the issue here?
The fractional part shows that the chemical entity we are dealing with here is a radical. While the integer 3 shows that there are 3 pi-bonds, the half pi bond remaining tells us that there is a missing electron on one of the atoms involved in the chemical bonding and as such, the 1/2 extra degree of unsaturation tends to tell us this.
Kindly recall that a radical is a chemical entity within which we have at the least an unpaired electron.
how do you make chocolate milk
Who were the terrorists that attacked the united states on September 11, 2001
Draw an important resonance form to show the delocalization of charge in the ion shown below.
Interactive 3D display mode
Answer:
Hello attached below is the missing ion diagram
Explanation:
Attached below is an important resonance form that shows the delocalization of charge in the ion shown
Among the elements magnesium, sodium and silicon, which hås the highest second ionisation
energy? Explain.
Answer:
Explanation:
silicon has highest ionization energy ionization energy increases from left to right in a period because electron are added to same shell and increase in added electron shield each other poorly from the nuclear attraction
The solubility of sugar at 50°C is 260/100g water,and at 0°Cis 180g/100g water. What mass of sugar,will be deposited if 60g the saturated solution at 50°C is cooled to 0°C
Explanation:
27 °0 bc that how it is so this is the answer
What will be the cost of gasoline for a 4,700-mile automobile trip if the car gets 41 miles per gallon, and the average price of gas is $3.79 per gallon?
Answer:
Idk
Explanation:
Find the gallons needed by dividing total miles by miles per gallon:
4700/41 = 114.634 gallons
Multiply the gallons needed by price per gallon:
114.634 x 2.79 = $319.83 Total
Round the answer as needed.
If gallons were rounded to 115 gallons total cost would be $320.85
$ 434.40
Explanation:41 miles ............ 1 gallon
4700 miles .......x gallon
x = 4700×1/41 = 114.63 gallons
114.63 gallons×$3.79 ≈ $ 434.40
someone help. what is the missing word?
a. acceleration
----------------------
brainly or jiskha
choose wisely
Answer:brainly
Explanation:
absolutely brainly
full of help and knowledge
what is the Si base unit of mass?
what is the base unit/1000 of mass?
what is the base unit×1000 of mass?
what is the base unit of liquid volume? what is the base unit/1000?
what is the base unit×1000?
what is the base unit of temperature? what is the base unit/1000?
what is the base unit×1000?
The SI unit of temperature is the kelvin (K), which spans the same temperature change as the degree Celsius. The Kelvin scale is a thermodynamic scale, meaning that its zero point is at absolute zero rather than the freezing point of water. The second reference point for this scale as it is currently defined is the triple point of water, which is a unique point on the phase diagram of water (a specific combination of pressure and temperature) where ice, liquid water and water vapor are all in equilibrium. The triple point is assigned the temperature of 273.16 K.
The old centigrade scale used the freezing and boiling temperatures of water as its reference points, with one degree centigrade equal to 1/100 of the temperature span between the freezing and boiling points of water. The definition of the Kelvin scale was chosen to make the kelvin the same size as the centigrade degree.
The Celsius scale is defined in terms of the Kelvin scale but is equivalent to the old centigrade scale, which it replaces. It is convenient for reporting weather and cooking temperatures and so on, but is not particularly useful for scientific purposes. For instance, the behavior of gases which approximate ideal gases is such that at zero degrees C they experience a volume change of 1/273 for a one degree change in temperature. This observation provided one of the first indications for the value of absolute zero.
When using the ideal gas law:
PV = nRT
where P is pressure
V is volume
n is the quantity of gas in moles
R is a constant
T is the temperature
it is necessary to use a thermodynamic scale, usually Kelvin.
Another thermodynamic scale, the Rankine scale, has a relationship to the Fahrenheit temperature scale analogous to that between the Kelvin and Celsius scales.
What is the mass, in grams, of the ethyl alcohol that exactly fills a 220 mL container? The density of ethyl alcohol is 0.789 g/mL. Group of answer choices 170 g 173.58 g 280 g 278.833967 g
Answer:
[tex]m=173.58g[/tex]
Explanation:
Hello,
In this case, since the density is the ratio of the mass and volume:
[tex]\rho =\frac{m}{V}[/tex]
For the given density and volume, the correct mass which fills the given volume is:
[tex]m=\rho *V=0.789g/mL*220mL\\\\m=173.58g[/tex]
Best regards.
The class measured the density of a copper block to be 8.6 +/-0.2 g/cm3 at the 95% confidence interval with a standard deviation of 0.4 g/cm. The true density of copper is 8.96 g/cm3.
a. What is the high and low number of the confidence interval range? Does the true value fall within the confidence interval?
high:
low:
within range?
b. What is the high and low of the standard deviation range? Does the true value fall within the standard deviation?
high:
low:
within range?
Answer: kindly check explanation
Explanation:
Given the following :
Measured density of copper block:
8.6+/-0.2 g/cm3
True density = 8.96g/cm3
Standard deviation = 0.4g/cm
a. What is the high and low number of the confidence interval range?
High : 8.6 + 0.2 g/cm3 = 8.8g/cm³
Low : 8.6 - 0.2 g/cm3 = 8.4g/cm³
Does the true value fall within the confidence interval? NO
Actual density = 8.96g/cm³ doses not lie in between (8.4 - 8.8)g/cm³
B.) High and low of the standard deviation range?
High = 8.6 + 0.4 = 9.0g/cm³
Low = 8.6 - 0.4 = 8.2g/cm³
Value falls within range of the true density value of copper block.
8.96g/cm³ falls in-between (8.2-9.0)g/cm³
chemical test of acetylene in the laboratory
Ahmed is trying to write a focused scientific question. "He writes, "Are the tides changing because of the Moon?" How could Ahmed's question best be rewritten
"Is the Moon's gravitational force affecting the tides on Earth?"
What is the term for a solution that is holding more dissolved solute than it should be able to at a particular temperature?
Explanation:
Sometimes, a solution contains more dissolved solute than is normally possible. This type of solution is said to be supersaturated. A saturated solution can become supersaturated if more solute is added while the temperature is raised.
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HELP !!
Question 5 Multiple Choice Worth 3 points)
(01.04 LC)
Which of the following is not an intensive physical property?
Magnetism
Boiling point
Thermal conductivity
Volume
It would be volume.
Volume is not an intensive property because it does change as the amount of substance increases or decreases. The rest of the properties are constant no matter the amount of substance.
Answer:
Volume
Look at the guy above me, okay-- they're smarter then me-
A liquid containing 55.0 wt% methanol (M), 5.00 wt% polyacrylate (P), and 40.0 wt% water (W) is distilled at steady-state into a top steam and a bottom stream. The total mass flow rates of the top and bottom streams are the same. The top stream has 85.0 wt% M and 0% P. a. Can you set a basis of calculation in this problem? Why or why not? b. Calculate the composition (mass fractions) in the bottom stream.
Answer:
a) YES ( Basis : F=100kg/h)
b) composition mass fraction in the bottom stream
(Xm)B = 0.25
(Xp)B = 0.1
(Xw)B = 0.65
Explanation:
a)
Can you set a basis of calculation in this problem? Why or why not?
Yes we can set a basis if calculation in this problem.
A good basis makes the calculation more easier. the problem are given in weight basis so we can choose basis of feed rate of 100kg/h
BASIS : 100kg/h
b)
given that;
mass flow rate of M in the feeds Mf = 0.55*F = 0.55*100 = 55kg/h
mass flow rate of p in the feeds Pf = 0.05*F = 0.05*100 = 5kg/h
mass flow rate of W in the feeds Pf = 0.40*F = 0.40*100 = 40kg/h
Now Balance
F = T + B
( but T=B)
so F = T + T = 2T
B = T = 50kg/h
TOP
mass flow rate of M in the top Mt = 0.85*T = 0.85*50 = 42.5 KG/H
mass flow rate of P in the top Pt = 0kg/h
mass flow rate of W in the top Wt = 0.15*T = 0.15*50 = 7.5kg/h
balance on M
Mf = Mt + Mb
Mb = Mf - Mt = 55kg/h - 42.5kg/h = 12.5kg/h
Balance on P
Pf = Pb + Pt
Pb = Pf - Pt = 5kg/h - 0kg/h = 5kg/h
Balance on W
Wf = Wt + Wb
Wb = Wf - Wt = 40kg/h - 7.5kg/h = 32.5kg/h
So bottom composition
mass fraction of M in Bottom XmB = Mb/B = (12.5kg/g) / (50kg/h) = 0.25
mass fraction of P in Bottom XpB = Pb/B = (5kg/g) / (50kg/h) = 0.1
mass fraction of W in Bottom XwB = Wb/B = (32.5kg/g) / (50kg/h) = 0.65
Uranium is a type of atom. In special circumstances that usually involve high amounts of energy, uranium can be broken. When this occurs, different pieces of the original atom remain, including a substance called plutonium. Which statement most likely describes plutonium? It will still be uranium, just smaller pieces of uranium. It must no longer be a form of matter. It must be a different kind of atom. It will be different than, but have the same properties as, uranium.
Answer:
It's c
Explanation:
I'm taking the test now on edge.
It must be a different kind of atom statement mostly likely describes plutonium. Hence option C is correct.
What are atoms?It is the smallest unit of matter that possess the properties of the chemical element. It can’t be an independently, they form ions and molecules they both are combine and form large numbers of matters.
Atoms are basically three types: Neutrons, protons and electrons.
In periodic table plutonium is above uranium. Plutonium is more powerful as compared to uranium because it is an isotope and more radioactive.
Almost all of naturally occurring. Uranium 92U238with a half-life of 4.468 x 109 year. Most rest of the natural uranium is92U235.
Uranium is generally used in the process of nuclear fission whereas plutonium is used for the production of nuclear weapons.
It must be a different kind of atom statement mostly likely describes plutonium. Hence option C is correct.
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The chemical 2,4-D causes liver decay in birds. True False
Answer:
no it cant
Explanation:
A substance made up of one type of atom is called an(a) ______________.
A. element
B. compound
C. atom
A substance that cannot be converted into another substance is known as an element. Each type of atom that makes up an element is unique. The correct option is A.
A substance whose atoms all contain the same number of protons is said to constitute an element; alternatively, all the atoms of a certain element must contain the same number of protons. Chemical reactions cannot degrade elements since they are the simplest chemical forms.
A compound is created when two or more components join chemically in a predetermined mass ratio.
Thus the correct option is A.
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What is the mass in grams of each of the following samples? 1.505 mol of Ti 0.337 mol of Na
Answer:
72.04g Ti and 7.75g Na
Explanation:
1.505 mol Ti x (47.87g/1 mol) = 72.04g Ti
0.337 mol Na x (22.99g/1 mol) = 7.75g Na
72.04g Ti and 7.75g Na mass in grams of these samples.
What is molecular mass ?Molecular mass can be determined by the measure of mass related to a molecule which is otherwise called as atomic weight, means the mass of every atom present in the molecule.
For example, water have 2 hydrogen atoms and 1 oxygen atom, the molecular mass of water is equals to the normal atomic mass of hydrogen increased by two or more the atomic mass of oxygen.
molecular mass can be controlled by many factors like Mass Spectrometry which is used to decide the mass of little molecule which is otherwise called as monoisotopic mass.
It can also be controlled by Hydrodynamic Strategy requires calibration and determine the relative atomic weight; Static Light Scattering where the Molecular weight is determined from the measure of light dispersed utilizing the Zimm technique.
So, 1.505 mol Ti x (47.87g/1 mol) = 72.04g Ti
0.337 mol Na x (22.99g/1 mol) = 7.75g Na, hence the answer is 72.04g Ti and 7.75g Na
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Draw the conjugate base for the acid (CH3)2C=OH+ Remember to include charges and non-bonding electrons where
necessary
Answer:
Explanation:
An acid is a substance that, when dissolved in water produces hydrogen ions, H⁺ as the only positive ion. e.g.
HCl ↔ H⁺ + Cl⁻
HNO₃ ↔ H⁺ + NO⁻₃
This process is known as ionization. The characteristics properties of an acid in solution are due to the presence of these hydrogen ions. In these reactions, the negative ions formed or sometimes the neutral compounds are usually known as the conjugate base of such acid.
From the given information, the conjugate base of the acid given can be seen in the attached image below.
The conjugate base for the acid is attached below.
What is an Acid?An acid is a substance that, when dissolved in water produces hydrogen ions, H⁺ as the only positive ion. e.g.
HCl ↔ H⁺ + Cl⁻
HNO₃ ↔ H⁺ + NO⁻₃
This process is known as ionization. The characteristics properties of an acid in solution are due to the presence of these hydrogen ions. In these reactions, the negative ions formed or sometimes the neutral compounds are usually known as the conjugate base of such acid.
The conjugate base of the acid given can be seen in the attached image below.
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Was the french revolution driving force behind the metric system?
Answer:
yes, they were
Explanation:
The history of the metric system began in the Age of Enlightenment with notions of length and weighttaken from natural ones, and decimal multiples and fractions of them. The system became the standard of France and Europe in half a century. Other dimensions with unity ratios[Note 1] were added, and it went on to be adopted by the world.
In the reaction between Li and O, there is a transfer of electrons making an ionic bond. In the bond, lithium would be a (n) because it an electron, and oxygen would be an) because it electrons. O A anion, loses, cation, gains B cation, gains, anion, loses Oc cation, loses, anion, gains O D anion, gains, cation, loses INTL 5
Answer:
C) cation, loses, anion, gains
Explanation:
Lithium is a metal from Group 1, so it has 1 valence electron. Thus, it loses 1 electron to complete its octet and form the cation Li⁺.
Oxygen is a nonmetal from Group 16, so it has 6 valence electrons. Thus, it gains 2 electrons to complete its octet and form the anion O²⁻.
In the reaction between Li and O, there is a transfer of electrons making an ionic bond. In the bond, lithium would be a cation because it loses an electron, and oxygen would be an anion because it gains 2 electrons.