How many electrons are there in the only energy level of helium, a noble gas? * Two Three Six Eight
Answer:
Explanation:
Noble gases are the least reactive of all known elements. That's because with eight valence electrons, their outer energy levels are full. The only exception is helium, which has just two electrons.
Arkeisha and Rodney are having a discussion about the correct use of the term "battery acid." Arkeisha insists that an alkaline battery does not have an actual acid contained within it, but Rodney disagrees and says that all batteries have acid in them. Which student is correct? A. Arkeisha is correct because the fluid in an alkaline battery has a pH between 0.0 and 6.9. B. Arkeisha is correct because the fluid in an alkaline battery has a pH between 7.1 and 14.0. C. Rodney is correct because the fluid in all batteries has a pH between 0.0 and 6.9, including alkaline batteries. D. Rodney is correct because the fluid in all batteries has a pH between 7.1 and 14.0, including alkaline batteries.
Batteries are filled with acidic fluid mostly of sulphuric acid. It have a pH about 0.8. Alkaline batteries are filled with potassium hydroxide or zinc chloride the pH is around 7 and the term battery acid cannot be used here. Thus option A is correct.
What is pH?pH of a solution is the measure of H+ ion concentration in the solution. It says how acidic or basic the solution is. If the solution has a pH of 7 it is neutral and if its less than 7 it is acidic and a pH of more than 7 is basic.
Battery is an electronic component which converts chemical energy to electrical energy. It consist of an electrolyte and two electrodes. Usually the fluid used in battery is sulphuric acid and it is called the battery acid.
Nowadays battery acids are replacing by alkaline fluids which are less hazardous than the acids. Most commonly potassium hydroxide, zinc chloride etc. are used as alkaline fluids.
The electrodes used in batteries are commonly zinc and magnesium. Thus, the pH of battery acid about 0.8 and option A is correct.
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Why are biopharmaceuticals in high demand?
Answer:
the market is largely driven by the growing population, increasing burden of chronic disease, and rising inclination toward targeted therapy.
Explanation:
also, the huge demand of biopharmaceutical is facilitated by an accelerating focus in research and related investment.
Consider the following unbalanced equation.
Ca(OH)2 + (NH2)2SO4 → CaSO4 + NH3 + H2O
Help for 70 points please explain why too.
Answer:
1 Ca(OH)2 + 1 (NH4)2SO4 ---> 1 CaSO4 + 2 NH3 + 2 H2O
Explanation:
The photo I attached should make more sense as an explanation.
When balancing equations, the first and most important step is to count the # of each type of element on each side.
In this problem there are 5: Ca, O, H, N, and S.
Once you do that you can begin balancing.
Here is the initial tally for the elements in this problem:
On the left.....
Ca - 1
N - 2
S - 1
O - 6
H - 10
On the right.....
Ca - 1
N - 1
S - 1
O - 5
H - 5
Looking at these values, we can see N, O, and H all need adjusting the right side. You should never start balancing with O or H unless they are the only elements that need adjusting. They usually balance out with the rest of your work or with water in the end.
So given all of that, you should start balancing with N on the right. Giving NH3 a coefficient of 2 will change the number of Nitrogen atoms on the right to 2. Be careful though! It will also change the number of Hydrogen atoms from 5 to 8 (because (2*3) =6 and 6+2 =8).
Let's tally our numbers again.
On the left..... (these should be unchanged)
Ca - 1
N - 2
S - 1
O - 6
H - 10
On the right.....
Ca - 1
N - 2
S - 1
O - 5
H - 8
Okay, now we see only O and H need adjusting on the right. Luckily there is H2O so we can do that without impacting the number of other atoms.
Give H2O a coefficient of 2 and count the number of atoms on the right again.
On the right.....
Ca - 1
N - 2
S - 1
O - 6 (because 4 from CaSO4 plus 2 from 2H2O = 6)
H - 10 (6 from NH3 plus 4 from 2H2O = 10)
Do these numbers match what you have on the the left side of the equation? Yes! It is balanced so you do not need to adjust anymore. Your coefficients in the answer will be 1-1-1-2-2.
Element X has two naturally occurring isotopes. The isotope with mass 62.93 amu has a
relative abundance of 69.2%. The isotope with mass 64.93 amu has a relative
abundance of 30.8%. Calculate the average atomic mass of Element X. What is the
identity of Element X?
when do meanders form in a river?
A.young
B.old
C.mature
D.rejuvenated
Answer:
The formation of a meander. As the river erodes laterally, to the right side then the left side, it forms large bends, and then horseshoe-like loops called meanders . The formation of meanders is due to both deposition and erosion and meanders gradually migrate downstream.
by . Figure the density of the liquid in each beaker: The mass and volume of each liquid have been given in Table 1. Using the formula for density and a calculator, figure the density of each liquid and record it in the density column of Table 1. Round and write your answer out to the nearest hundredth. (This means you will have two numbers after the decimal point.) Don't forget to write the units!!!!!! (Hint: The formula was the answer to #2 on the front page.)
Answer:
Well what are the numbers but ik that it ius 5
Explanation:
Answer question number 2
Answer:
it would be the second choice
During the Metric Olympics yesterday, Molly's long jump was 118.3 cm. Christy accidentally recorded her results in inches. She jumped 51.18 inches. Can you help... Who won the long jump? Christy won by about 30 cm Christy won by about 30 cm Molly won by about 25 cm Molly won by about 25 cm Christy won by about 12 cm Christy won by about 12 cm Molly won by about 10 cm
Answer: Christy won Molly by 12cm
Explanation:
Ist step
Molly's ;ong jump was 118.3cm
Christy long jump was 51.18inches
2nd Step
we change christy score to cm so we can compare
1 inch = 2.54cm.
therefore 51.18 inches = 51.18 x 2.54= 129.9972cm
Christy won molly by 129.9971cm-118.3cm=11.69 rounded to 12cm
Christy won Molly by 12cm
How many meters is a 50 yards olympic size swimming pool?
Answer:
An official Olympic Sized pool is 50 meters long by 25 meters wide.
Explanation:
Match the terms below to the correct definitions
3. Atom
1. The mass on the periodic table.
b. Electrons
2. Region surrounding the nucleus where electrons are found.
C. Protons
3. Positively charged center of an atom.
d. Neutrons
4. Particles that differ in number between isotopes.
e. Electron
cloud
5. Vertical column in the periodic table.
1. Nucleus
6. Positively charged particles in an atom.
R. Quark
7. Negatively charged particles in the outermost energy levels of the electron cloud.
8. Table that organizes the elements by properties.
9. Atoms of the same element that have different masses.
h. Atomic
number
1. Mass number
10. Smallest known particle that makes up protons and neutrons.
j. Average
atomic mass
11. All elements in the same one of these has the same number of energy levels in
their electron cloud.
k. Isotopes
12. The smallest form of matter that still retains the properties of an element.
1. Valence
electrons
13. Negatively charged particles in an atom.
m. Group
14. The sum of protons and neutrons in an atom.
n. Period
15. Represents the identity of an element.
o. Periodic
Table
Answer:
Explanation:
1=i
4=d
5=m
6=c
8=o
9=j
10=a
13=b
14=h
15=l
Theses are the ones i knew
Which statement describes a molecule that has a trigonal pyramidal molecular shape?
The molecule has a trigonal planar electron domain geometry with one lone pair.
O The molecule has a tetrahedral electron domain geometry with one lone pair.
O The molecule has a trigonal planar electron domain geometry with two lone pairs.
O The molecule has a tetrahedral electron domain geometry with two lone pairs.
The statement describes a molecule that has a trigonal pyramidal molecular shape is "The molecule has a trigonal planar electron domain geometry with two lone pairs".
So, option C is correct one.
What is difference between shape and geometry of the molecule?In finding geometry of the molecule, lone pairs and bond pairs both are included but in finding shape of the molecule only bond pairs are are involve.
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Answer:C
Explanation: Took the test
Surface water is found in oceans, lakes, reservoirs, streams, rivers,and glaciers. Lakes, rivers, and reservoirs are where humans obtain most of the surface water they use. Aquifers are an underground source of water that humans also use.
A student measures the mass and volume of a
substance and calculates its density as 1.40 g/mL. The
correct, or accepted, value of the density is 1.30 g/mL.
What is the percentage error of the student's
measurement?
Answer:
The answer is 7.69 %Explanation:
The percentage error of a certain measurement can be found by using the formula
[tex]P(\%) = \frac{error}{actual \: \: number} \times 100\% \\ [/tex]
From the question
actual number = 1.30 g/mL
error = 1.40 - 1.30 = 0.1
We have
[tex]p(\%) = \frac{0.1}{1.3} \times 100 \\ = 7.692307...[/tex]
We have the final answer as
7.69 %Hope this helps you
Help plzzzzz ASAP!!!!!!!
Answer:
3. The total number of protons and neutrons in an atom is its mass number.
4. The mass number of a helium atom with 2 protons and 2 neutrons is 4.
5. A beryllium atom with 4 protons and a mass number of 9 has 5 neutrons.
6. The chemical symbol is Ne. The atomic number is 10. The mass number is 22.
7. Neon-22
8. Not enough information
A substance can change into a new kind of molecule when:
Answer:
Chemical changes cause a substance to change into an entire substance with a new chemical formula. Chemical changes are also known as chemical reactions. The “ingredients” of a reaction are called reactants, and the results are called products.
Hope it helps
Scientists and nutritionists have long suspected that high-fructose corn syrup, used to
sweeten soft drinks, is one of the causes of childhood obesity. In a recent study, at the
University of Cincinnati, researchers found that mice that drank water with added
fructose ate less solid food, gained more weight, and put on 90% more body fat than
mice that drank only water. Scientists concluded that fructose may affect metabolism in
a way that favors fat storage.
What is the independent variable?
The mice that drank only water
The presence of fructose in their diet
The quantity of water provided
The weight gained by the mice
Answer:
The presence of fructose in their diet
Explanation:
The independent variable in an experiment is the type of variable which is changed at intervals in order to study if it has a direct effect on the dependent variable.
The dependent variable in the experiment is the amount of weight gained by the mice in each group and the control group is the mice who drank the water without the fructose added.
Where do we live a.Troposphere b.Thermosphere c. Mesosphere D.Stratosphere
Answer:
troposphere
Explanation:
Answer:
Hello!!! Princess Sakura here ^^
Explanation:
We live in the troposphere since 99% of the water vapor in the atmosphere is found here.
Is the study of the living plants and animals in the ocean
Answer:
marine biologist
Explanation:
marine biologist
Answer:
marine biologist a scientist who studies creatures that live in ocean water, from bacteria and shellfish to kelp and whales. mean One of several measures of the “average size” of a data set. .organism Any living thing, from elephants and plants to bacteria and other types of single-celled life.
Which of the following is true about metals?
A. They are usually less reflective in luster than metalloids.
B.
They are usually better conductors than nonmetals.
C. They are usually less malleable than nonmetals.
D.
They are usually more brittle than metalloids.
A scientist is examining a mixture of nitrogen, hydrogen, and ammonia. The individual pressures that are exerted by nitrogen and hydrogen are 0.26 atm and 0.28 atm, respectively. If the total pressure is 0.90 atm, what is the partial pressure of ammonia? Use P subscript T equals P subscript 1 plus P subscript 2 plus P subscript 3 plus ellipses plus P subscript n.. 0.27 atm 0.36 atm 0.54 atm 0.90 atm
Answer: 0.36 atm
Explanation:
According to Dalton's law, the total pressure is the sum of individual pressures.
[tex]p_{total}=p_1+p_2+p_3[/tex]
Given : [tex]p_{total}[/tex] = total pressure of gases = 0.90 atm
[tex]p_{N_2}[/tex]= partial pressure of nitrogen = 0.26 atm
[tex]p_{H_2}[/tex] = partial pressure of hydrogen = 0.28 atm
[tex]p_{NH_3}[/tex]= partial pressure of ammonia = ?
putting in the values we get:
[tex]0.90=0.26 +0.28+p_{NH_3}[/tex]
[tex]p_{NH_3}=0.36atm[/tex]
Thus the partial pressure of ammonia is 0.36 atm
Answer:
B) 0.36 atm
Explanation:
Which of the following is an example of how pictures of a planet's surface can provide evidence about the planet's natural resources?
Answer:
it can show how much green is left. and how climate change is going, and the cloud shows how much oxygen is left in the air.
What is the mass of 4.39 mol Na?
Answer:
101 g Na
Explanation:
To convert between moles and grams, you have to use the molar mass of the substance. The molar mass of sodium is 22.99 g/mol. You use this as the unit converter.
[tex]4.39molNa*\frac{22.99gNa}{1molNa} = 100.9261gNa[/tex]
Round the number to the lowest number of significant figures; 101 g Na.
The mass of 4.39 moles of sodium (Na) is 100.97grams.
HOW TO CALCULATE MASS:The mass of a substance can be calculated by multiplying the number of moles in the substance by its molar mass. That is;Mass = no. of moles × molar mass
According to this question, there are 4.39 moles of Na. The molar mass of Na is 23g/mol.Mass of Na = 4.39 × 23
Mass of Na = 100.97grams.
Therefore, mass of 4.39 moles of sodium (Na) is 100.97grams.
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Unit: Scientific Measurement“One, Two, and More Step Problems” – Wksh #2
1.How many g are equal to 345.7 mg?
2.Change 0.00765 kL into mL.
3.How many seconds are there in 2.5 days?
4.How many minutes are there in 1.000 week?
5.How many seconds long is this chemistry class if it lasts 40.0 minutes?
6.A chemistry student’s height is measured at 68.5 inches. How tall is the student in cm?
7.This same chemistry student has a weight of 155 lbs. What is the student’s weight ingrams? (16oz=1lb, 1 oz = 28.34 g)
8.A homerun in a baseball game was measured at 450 feet. How many meters is this equalto?
9.Mount Everest is approximately 8,000 meters high. How many miles high is MountEverest?
10.A 5.0 km race is scheduled for this weekend. How many miles is this race?
Answer:
1. 0.3457g
2. 7650mL
3. 216000 seconds
4. 10080minutes
5. 2400 seconds
6. 173.99cm
7. 70283.2g
8. 137.16metres
9. 4.968miles
10. 3.105miles
Explanation:
1. 1000mg = 1g
345.7 mg = 345.7/1000
= 0.3457g
2. 1kL = 1000000mL
0.00765 kL = 0.00765 × 1000000
= 7650mL
3. 1 day = 86400s
2.5 days = 2.5 × 86400
= 216000 seconds
4. 1 week = 10080minutes
1.000weeks is equivalent to 1 week, hence there are 10080minutes in 1.000week.
5. 1minute = 60seconds
40.0minutes = 40 × 60
= 2400seconds.
6. 1 inch = 2.54cm
68.5inches = 68.5 × 2.54
= 173.99cm
7. 1Ib = 16oz
155Ibs = 155 × 16
= 2480 oz
1 oz = 28.34 g
2480oz = 2480 × 28.34
= 70283.2g
8. 1 foot = 12 inches
450 feet = 450 × 12
= 5400inches
1 inch = 0.0254metres
5400 inches = 5400 × 0.0254
137.16metres
9. 1 metre = 0.000621 mile
8000 metres = 8000 × 0.000621
= 4.968miles
10. 1 kilometers = 1000 metres
5km = 5 × 1000
= 5000metres
1 metre = 0.000621 mile
5000metres = 5000 × 0.000621
= 3.105miles
Which is the name of O3?
dioxide
oxygen
trioxygen
monoxide
The answer is C, Trioxygen
The name for O₃ molecule is trioxygen as it is made up of three oxygen atoms.
What is an atom?An atom is defined as the smallest unit of matter which forms an element. Every form of matter whether solid,liquid , gas consists of atoms . Each atom has a nucleus which is composed of protons and neutrons and shells in which the electrons revolve.
The protons are positively charged and neutrons are neutral and hence the nucleus is positively charged. The electrons which revolve around the nucleus are negatively charged and hence the atom as a whole is neutral and stable due to presence of oppositely charged particles.
Atoms of the same element are similar as they have number of sub- atomic particles which on combination do not alter the chemical properties of the substances.
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What do these two changes have in common?
sauce burning on a stove
dry ice sublimating and becoming a gas
Select all that apply.
Both are caused by heating.
Both are only physical changes.
Both conserve mass.
Both are chemical changes.
Answer:
Both are caused by heating and both are physical and chemicals.
Explanation:
The similarity between the two changes that have common things are
A. Both are caused by heating.
C. Both conserves mass.
D. Both are chemical changes.
What are chemical and physical changes?The term “physical change” refers to a change in an object's appearance. When there is a change in the surroundings of the object, such as a rise in temperature or pressure, a physical change takes place.
When candles are burned, the wax melts, but as soon as the temperature drops, the wax hardens and solidifies once more.
Here, chemical changes happen because these changes can not be undone again. When a substance changes their appearance, they always have the same mass.
Thus, the correct options are A. Both are caused by heating, C. Both conserve mass, and D. Both are chemical changes.
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Describe the relationship between an element and a compound.
Answer:
An element is a material that consist of a single type of atom . each atom type contains same number of protons . chemical bonds link elements to form more complex molecules called compound A compound consist of two or more elements held together by covalent or ionic bonds.
are you clear?
A student places a small amount of water in a glass dish and then carefully places a small paperclip on the surface of the water. The paperclip floats. What happens if the student adds a drop or two of dish soap to the water?
Answer:
Adding soap would cause the paper clip to fall through the water and onto the base of the dish because soap is a surfactant.
Explanation:
The concept surface tension is used here to determine what happens to the paperclip when a drop of dish soap is added to the water. Here the paperclip sink into the water.
What is surface tension?The property exhibited by the surface of a liquid in order to resist the action of an external force because of the cohesive nature of the molecules is known as the surface tension. Due to this property the surface of a liquid behaves as an extended elastic membrane.
The paperclip float on water because of the high surface tension as the water molecules at the surface are strongly attracted among themselves. But on adding one or two drops of dish soap to water causes the paperclip to sink.
The addition of the drops of dish soap to the water weakens the attraction among the water molecules and thereby lowers the surface tension. As a result of this the surface film disappears and the paperclip sink into the water.
Thus the paperclip fall into the water when a drop of dish soap is added to the water.
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at room temperature oxygen gas travels at 393.5 meters per second. How fast does oxygen travel in mile per hour ?
Answer:
Oxygen travels in 1,416,600
Explanation:
Calculate the molarity of a NaOH solution that is prepared by diluting 100mL of 0.20M NaOH with 150mL of H2O.
Molarity of solution = 0.08 M
Further explanationMolarity shows the number of moles of solute in every 1 liter of solution or mmol in each ml of solution
[tex]\tt M=\dfrac{n}{V}[/tex]
Where
M = Molarity
n = number of moles of solute
V = Volume of solution
mol of NaOH[tex]\tt mol=0.2~M\times 100~ml=20~mlmol=0.02~mol[/tex]
molarityVolume of solution = 100 ml + 150 ml = 250 ml
[tex]\tt M=\dfrac{0.02~mol}{0.250~L}=0.08[/tex]