Answer:
Explanation:
The last number in a measured number is always an estimated digit.
In an electrically neutral atom,
o the number of protons equals the number of
neutrons.
the number of protons equals the number of
electrons.
the number of neutrons equals the number of
electrons.
Answer:
the number of Protons equals the number of Electrons.
Explanation:
Edg 2021
In an electrically neutral atom, the number of protons equals the number of electrons. Thus, the correct option for this question is B.
What are Protons?Protons may be defined as the type of sub-atomic particles that are present in the nucleus of an atom along with neutrons. These sub-atomic particles are positively charged in nature. Protons are thought to be discovered by Ernest Rutherford.
Electrons are also the type of sub-atomic particles which are continuously revolving around the nucleus of an atom. These sub-atomic particles are negatively charged in nature.
So, when the number of protons is more as compared to the number of electrons, an atom possesses a positive charge while the number of protons is found to be less compared to the number of electrons, and an atom possesses a negative charge.
Therefore, in an electrically neutral atom, the number of protons equals the number of electrons. Thus, the correct option for this question is B.
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If and acid has a Ka dissociation constant of 1 x 10-9 what is the pKa of this acid?
Answer:
pKa = 9
Explanation:
In this case, we have to remember the meaning of "p". When we use "p" in any calculation we have to apply the minus ten based logarithm, so:
[tex]p~=~-Log[/tex]
For example, when we use the "pH" value. We have to apply the minus ten based logarithm of the concentration of the hydronium ion:
[tex]pH~=~-Log[H^+][/tex]
So, if we have wanted to calculate the pKa value. We have to apply the minus ten based logarithm of the Ka value, so:
[tex]pKa~=~-Log~Ka[/tex]
Now we can plug the value into the equation:
[tex]pKa~=~-Log~1x10^-^9[/tex]
[tex]pKa~=~9[/tex]
The pKa value is 9.
I hope it helps!
It is desired to make 1.00 liter of 6.00 M nitric acid from concentrated 16.00 M HNO3.A) How many moles of nitric acid are in 1.00 L of 6.00 M nitric acid?B) What volume of concentrated 16.00 M nitric acid will contain this number of moles?C) If this volume of concentrated nitric acid (answer to b) is diluted to 1.00 liter, what will be the molarity of the solution?
Answer:
A) 6.00 mol.
B) 0.375 L or 375 mL
C) 6.00 M
Explanation:
Hello,
A) In this case, from the definition of molarity, we compute the moles for the given volume and concentration:
[tex]n=M*V=1.00L*6.00mol/L=6.00mol[/tex]
B) In this case, from the stock solution, the required volume is:
[tex]V=\frac{6.00mol}{16.00mol/L}=0.375L[/tex]
C) In this case, we apply the following formula for dilution process:
[tex]M_1V_1=M_2V_2[/tex]
Thus, solving for the final molarity, we obtain:
[tex]M_2=\frac{M_1V_1}{V_2}=\frac{16.00M*0.375L}{1.00L}\\ \\M_2=6.00M[/tex]
Regards.
How important are minerals in our daily lives?
Explanation:
minerals are common in vitamin product iron and calciumall provide day to day nutrients dad the bmicoody needs in order to function food that are full of
Answer:
It is very important in our lives....
Explanation:
It is used to create the materials,used in construction of roads and buildings,they also serve as critical components in the manufacturing of high tech electronics.
A box is pushed down at an angle of 32 degrees on a rough surface. The box moves to the right.
A picture of a woman pushing downward at an angle of 32 degrees with the horizontal on a box. There is a dot in the center of the box and a force pointing southeast away from it labeled F Subscript p.
What equation should be used to find the net force in the y-direction?
F subscript net, y = F subscript N minus F subscript g.
F subscript net, y = F subscript p minus F subscript f.
F subscript net, y = F subscript N minus F subscript g minus F subscript p cos(32).
F subscript net, y = F subscript N minus F subscript g minus F subscript p sin(32).
Answer:
F subscript net, y = F subscript N minus F subscript g minus F subscript p sin(32).
Explanation:
F subscript net, y = F subscript N minus F subscript g minus F subscript p sin(32).
Forces acting on box :
We have four forces acting on the box. Taking the upward direction as positive direction for the vertical axis:
- The push, which pushes down along the ramp inclined at 32 degrees. Its vertical component will be , where F is the magnitude of the push
- The weight of the box, of magnitude , with m being the mass of the box and g being the acceleration of gravity (9.8 m/s^2). This force is already directed vertically downward, so we don't need to resolve it into the vertical direction
- The frictional force, of magnitude , where is the coefficient of friction, directed upward along the inclined plane. Its vertical projection will be
- The normal reaction, whose magnitude is equal to the component of the weight perpendicular to the inclined plane, but with opposite direction (upward): . If we resolve it along the vertical direction.
So, the net force along the y-direction will be:
F subscript net, y = F subscript N minus F subscript g minus F subscript p sin(32).
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How many mL are equal to .0024 L?
Answer:
1
Explanation:
1000ml=1l
? =0.0024l
0.0024/1000×1
0.0000024ml
Volume has been the amount of space covered and occupied by the substance. The volume of the substance has 0.0024 liters is equivalent to 2.4 milliliters.
What is volume?Volume has been defined as the three-dimensional space that has been occupied by the substance in space. It has been measured in derived units of length like cubic meter (m³), cubic centimeter (cm³), liter (l), and milliliter (ml).
The units of the volume can be converted into various derived units by multiplication and division of the units. The small units are derived from larger ones by multiplying and larger units are converted into smaller ones by division.
Given,
Volume = 0.0024 L
Converting units as:
1 liter = 1000 mL
0.0024 L = 2.4 mL
Therefore, the volume is 2.4 milliliters.
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Question 3(Multiple Choice Worth 3 points)
(01.02 LC)
What is the metric unit for mass?
O Meters
O Kilograms
O Pounds
O Matter
Answer:
kilograms
Explanation:
Answer:B) Kilograms
Explanation:I took the test and got it right!
What is the volume of 1.50 lb (pounds) of mercury? The density of mercury is 13.546 g/mL. Use the conversion that 1 kg = 2.20 lb. mL.
Answer:
50.3mL of mercury are in 1.50lb
Explanation:
Punds are an unit of mass. To convert mass to volume we must use density (13.546g/mL). Now, As you can see, density is in grams but the mass of mercury is in pounds. That means we need first, to convert pounds to grams to use density and obtain volume of mercury.
Mass mercury in grams:
1.50lb * (1kg / 2.20lb) = 0.682kg = 682g of mercury.
Volume of mercury:
682g Mercury * (1mL / 13.546g) =
50.3mL of mercury are in 1.50lbList 5 characteristics of a living thing
Answer:
1.Growth.
2 Reproduction.
3.respond to stimuli
4.are made from more than 1 cell
5.need energy to live
hope this helped
5 pois
Energy pyramids illustrate the transfer of 10% of the energy stored by
producers flowing from the bottom level to primary consumers. What
happens to the other 90% of the energy?
О
The remaining 90% is transformed for life activities such as movement, growth, or
released as heat.
The remaining 90% evaporates into the atmosphere.
The remaining 90% transforms into Hydrogen and Oxygen.
The remaining 90% is recombined to maker larger molecules.
In the metric system, the ________ describes the relationship of each unit to the base unit.
a. suffixb. none of the answer choices are correct.c. synonymd. punctuatione. prefix
Answer:
prefix
Explanation:
In a metric system the prefix shows the relationship of each unit to the base unit.
The metric system is an international system of measurement that uses base units of meter for measuring distance, liter for measuring volume and grams for measuring mass.
The metric unit can be smaller or bigger than the base unit, hence, when using the metric system, the prefix shows the relationship between each unit to the base unit.
Thus, we can conclude that the prefix shows the relationship of each unit to the base unit.
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is xenon (xe) more or less reactive than bromine (br)? why?
Answer:
Xenon is less reactive.
Explanation:
Xenon is a noble gas with 8 valence electrons whereas bromine is a halogen with 7 and is very reactive.
Two or more than two atoms with different physical or chemical properties can not combine together to form an element. Therefore, xenon (xe) is less reactive than bromine (br) as xenon has noble gas electronic configuration.
What is element?Element generally consist of atoms or we can atoms combine to form element. Atoms of an element is always same, means all the properties of all atoms of one type of element is same.
Xenon (xe) is a 18 group element of a periodic table. The electronic configuration of these are of noble gas. Noble gases are very unreactive. These can't react at even harsh condition. Bromine belongs to group 17 of parodic table that is to halogen family. Halogens have high electronegativity. these are very reactive. the ere one electron less than the noble gas electronic configuration.
Therefore, xenon (xe) is less reactive than bromine (br) as xenon has noble gas electronic configuration.
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how many pi bonds do triple bonds have
Answer:
Two pi bonds, one sigma bond.
Explanation:
A triple bond has three bonds:
2 pi bonds, and one sigma bond.
Answer:
Two pi bonds & one sigma bond.
A triple bond is made of:
2 pi bonds1 sigma bondHope it helps!
Desceibe each of the following as a measured number or an exact number:5 books5 Ib9.23 g0.035 kg12 roses12 inches in 1 foot361 miles100 cm in 1 mHow do you determine the last digit in any measured number?
Answer:
The last digit in any measured quantity of a tool is the minimum it can measure so
5 books ---- Exact number
5 lb ---- measured
9.23 g----- measured
9.035Kg measured
12 roses ------ exact
12 inches in 1 foot ----- exact
361 miles ------- measured
100 cm in 1 m ------- exact
A mountaineer shouts for help Half a second later (0.5 she hears the echo How far away is the rock face which is reflecting her voice (take the speed of sound to be 330 m\s) help please I will mark brain liest
Answer:
THE DISTANCE OF THE ROCK REFLECTING HER VOICE IS 82.5 METERS.
Explanation:
In sound waves, the speed of a sound is equal to twice the distance divided by time.
Mathematically,
Speed = 2 * Distance/ Time
Speed = 33- m/s
Time = 0.5 second
Distance = unknown
So re-arranging and introducing the variables into the formula, we have;
Distance = speed * time / 2
Distance = 330 * 0.5 / 2
Distance = 82.5 meters.
The distance away from the rock face which is reflecting her voice is 82.5 meters.
Challenge: In a 60 km/h speed zone the police set up a digitector, placing 2 cables across the road, 5m apart The time taken for cars to cross both cables was recorded. One car took 0.2 seconds to cross the cables. Was it speeding? If so by how much?
Answer:
The answer to your question is given below.
Explanation:
The following data were obtained from the question:
Speed limit = 60 km/h
To know if the car was speeding, let us calculate the speed of the car.
This can be obtained as follow:
Distance (d) = 5 m
Convert 5 m to km
Recall:
1000 m = 1 km
5 m = 5/1000
5 m = 0.005 km
Time (t) = 0.2 sec.
Convert 0.2 sec to hour.
Recall:
3600 secs = 1 h
Therefore,
0.2 sec = 0.2/3600
0.2 sec = 5.56×10¯⁵ h
Thus,
Distance (d) = 0.005 km
Time (t) = 5.56×10¯⁵ h
Speed of car =?
Speed = Distance /time
Speed = 0.005/5.56×10¯⁵
Speed of the car = 90 km/h
Comparing the speed of the car (i.e 90 km/h) to the speed limit of the zone (i.e 60 km/h), we can see that the car is on a high speed since its speed (i.e 90 km/h) is higher than the speed limit of the zone (i.e 60 km/h).
Speed of the car = 90 km/h
Speed limit = 60 km/h
Difference = 90 – 60
Difference = 30 km/h
Therefore, the car is speeding by 30 km/h more compared to the speed limit.
Express the following in proper exponential notation.
A. 1512 =
B. 0.00529 =
C. 21.52 X 10^-4
Answer:
A. 1.512*10^3
B. 5.29*10^-3
C. 2.152*10^-3
Explanation:
Exponential notation is where a number is represented in the form:
x * 10^n
where x is a number between 1 and 10.
In order to represent 1512 as a number between 1 and 10, we need to divide it by a multiple of 10. In this case, dividing is by 1000 will move it 3 decimal places to the left and get us 1.512 which is perfect. Because we divided by 1000 to get there, 1.512 needs to multiply by 1000 to equal the original number 1512. Since 1000 = 10^3, 1512 in exponential form is:
1.512*10^3
Similarly for the other ones:
0.00529 we need to multiply by 1000 to get to 5.29 (between 1 and 10) so this needs to multiply by 0.001 (1/1000) to equal original number so in exponential form is:
5.29*10^-3 (10^-3 = 0.001)
Finally:
21.52*10^-4 I would recommend converting back to the original number first, which would give us:
21.52*0.0001 = 0.002152
Which we need to multiply by 1000 to get right number so in exponential form is:
2.152*10^-3
Hope this helped!
Can a model be improved so much that it leads to truth? Explain your answer.
Answer:
yes it can
Explanation:
a model can be improved so much that it increases your chances of (insert what ever you are writing about) and then describe why:)
From his experiments, J. J. Thomson concluded that cathode ray particles can move at very fast speeds. cathode ray particles can be moved by electric current. atoms contain small positively charged particles that are called protons. atoms contain small negatively charged particles that are called electrons. Mark this and return
Answer:atoms contain small negatively charged particles that are called electrons
Explanation:
Find the density of a moving box that weighs 898 grams and has a volume of 300 cm3.
Answer:
d ≈ 3 g/cm³
Explanation:
Density Formula: d = m/v
Step 1: Define variables
mass m = 898 grams
volume v = 300 cm³
Step 2: Substitute and evaluate
d = 898 g/300 cm³
d = 2.99333 g/cm³
d ≈ 3 g/cm³ (1 sig fig)
Convert 1,650,000 centimeters to kilometers.
0 1.65 kilometers
16.5 kilometers
0 165 kilometers
1,650 kilometers
Answer:
16.5 kilometers is your answer
Answer:
16.5
Explanation:
what is connecting wire in science
Answer:
Connecting wires provide a medium to an electrical current so that they can travel from one point on a circuit to another. ... In a basic circuit, the wire comes from one terminal of a power source, then connects to a switch that determines whether the circuit is open or closed.
Explanation:
Whose work directly resulted in the development of an atomic model that has negative electrons stuck within a sea of positive material? Democritus Rutherford Thomson Dalton
Answer:
Thomson
Explanation:
Atomic models were proposed after the discovery of the atom and the sub-atomic particles. Thomson's model of the atom portrayed electrons stuck in the sea of protons. Thus, option C is correct.
What is Thomson's atomic model?J. J. Thomson proposed the model for atoms and their sub-atomic particles called electrons and protons. It was an important model that depicted the presence of the sub-atomic particles in the atom.
According to him, the electron had been known to carry a negative charge that was stuck in the soup or the sea of the positively charged protons. It resembled a plum cake that has electrons stuck in them as the cherries or the plum.
Therefore, the atomic model of the electron stuck in the sea of protons was given by J. J. Thomson.
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Rank the following compounds from most acidic to least. To rank items as equivalent, overlap.A. CH3NH2B. CH3OH+C. 2CH3OH
pls explain how the energy of a marble is transformed as it rolls down a ramp.
Answer:
Energy is not created but transformed meaning the energy just transformed into a different type meaning at all points of the ramp the energy stays the same because all of its energy is just transformed into kinetic energy.
Explanation:
Classify the organic compounds by the class of their functional group. Drag the appropriate items to their respective bins.CH3COCH2CH2CH2CH3 CH3CH2COOH CH3CH2CH2CHO CH3CH2CH2NH2 Carboxylic acid Amine Ketone Aldehyde Alcohol
Answer:
Explanation:
CH₃COCH₂CH₂CH₂CH₃ ------- Ketone because it contains C = O group .
CH₃COH=CHCH₂CH₂CH₃ ------ Alcohol group because it contains - OH group .
CH₃CH₂COOH ---- Carboxylic group because it contains - COOH group.
CH₃CH₂CH₂CHO ------- Aldehyde group because it contains - CHO group
CH₃CH₂CH₂NH₂ ----- Amine group because it contains - NH₂ group .
The compounds can be categorized as, Carboxylic acid: [tex]\rm CH_3CH_2COOH[/tex]; Amine: [tex]\rm CH_3CH_2CH_2NH_2[/tex]; Ketone: [tex]\rm CH_3COCH_2CH_2CH_2CH_3[/tex]; Aldehyde: [tex]\rm CH_3CH_2CH_2CHO[/tex], and Alcohol: [tex]\rm CH_2COH=CHCH_2CH_2CH_3[/tex].
Organic compounds are the hydrocarbons that has been divided based on the functional groups. The compounds that fall into the following category are:
Carboxylic acid: These are compounds with the presence of carboxylic group -COOH. The carboxylic compound has been [tex]\rm CH_3CH_2COOH[/tex].Amine: These are compounds with the presence of amine group -[tex]\rm NH_2[/tex]. The amine compound has been [tex]\rm CH_3CH_2CH_2NH_2[/tex].Ketone: These are compounds with the presence of ketone group -C=O. The ketone compound has been [tex]\rm CH_3COCH_2CH_2CH_2CH_3[/tex].Aldehyde: These are compounds with the presence of aldehyde group -CHO. The aldehyde compound has been [tex]\rm CH_3CH_2CH_2CHO[/tex].Alcohol: These are compounds with the presence of hydroxyl group -OH. The alcohol compound has been [tex]\rm CH_2COH=CHCH_2CH_2CH_3[/tex].The compounds can be categorized as, Carboxylic acid: [tex]\rm CH_3CH_2COOH[/tex]; Amine: [tex]\rm CH_3CH_2CH_2NH_2[/tex]; Ketone: [tex]\rm CH_3COCH_2CH_2CH_2CH_3[/tex]; Aldehyde: [tex]\rm CH_3CH_2CH_2CHO[/tex], and Alcohol: [tex]\rm CH_2COH=CHCH_2CH_2CH_3[/tex].
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A car traveling north with a velocity of 30 m/sec slows down to a velocity of 10 m/sec
within 10 sec. What is the car's acceleration?
Answer:
-2m/s/s
Explanation:
Acceleration = change in speed / change in time
Change in speed = final speed - initial speed
In this case the change in speed was 10m/s - 30m/s = -20m/s
And change in time was 10 sec (within 10 sec)
Therefore acceleration = -20/10 = -2m/s/s
The acceleration is negative because the car slowed down (decelerated essentially) and the unit for acceleration is meters per second per second because it is the change in speed per second.
Hope this helped!
When hafnium metal is heated in an atmosphere of chlorine gas, the product of the reaction is found to contain 62.2 percent Hf by mass and 37.4 percent Cl by mass. What is the empirical formula for this compound?
Answer:
HfCl3
Explanation:
Step 1
Divide the percent by mass of each element by its relative atomic mass
Hf- 62.2/178.5, Cl-37.4/35.5
0.348, 1.054
Step2
Divide through by the lowest ratio
0.348/0.348, 1.054/0.348
1, 3
Therefore the empirical formula is HfCl3
Classify each of the following values by the number of significant figures present in each. 8.314 J/mol-K 6.022x10 23 mol-1 12 mL 1.2 years 7.0 m2 50, cm 0,005 L 40.7 g 670.90 in 0.6258 mg 2.205 lb 3270 ft 90 m 5 significant 4 figuressignificant 3 figuressignificant 2 figuressignificant 1 figures
Answer:
5 significant figures: 670.90 in.
4 significant figures: 8.314 J/mol-K, 6.022x10 23 mol-1, 0.6258 mg, 2.205 lb and 3270 ft.
3 significant figures: 40.7 g.
2 significant figures: 12 mL, 1.2 years, 7.0 m2, 50, cm and 90 m.
1 significant figure: 0,005 L.
Explanation:
Hello,
In this case, we proceed as follows:
* 8.314 J/mol-K has 4 significant figures since 8, 3, 1 and 4 are significant (nonzero).
* 6.022x10 23 mol-1 has 4 significant figures since 6, 0, 2 and 2 are significant including the zero as it is at the right of the first nonzero digit (6).
* 12 mL has 2 significant figures since 1 and 2 are significant (nonzero).
* 1.2 years has 2 significant figures since 1 and 2 are significant (nonzero).
* 7.0 m2 has 2 significant figures since 1 and 2 are significant (nonzero).
* 50, cm has 2 significant figures since 1 and 2 are significant (nonzero).
* 0,005 L has 1 significant figure since 5 is the only nonzero digit.
* 40.7 g has 3 significant figures since 4, 0 and 7 are significant including the zero as it is at the right of the first nonzero digit (4).
* 670.90 in has 5 significant figures since 6, 7, 0, 9 and 0 are significant including the zeros as they are at the right of the first nonzero digit (6).
* 0.6258 mg has 4 significant figures since the first zero is at the left of the first nonzero digit, therefore, it is not included.
* 2.205 lb has 4 significant figures since 2, 2, 0 and 5 are significant including the zero as it is at the right of the first nonzero digit (2).
* 3270 ft has 4 significant figures since 3, 2, 7 and 0 are significant including the zero as it is at the right of the first nonzero digit (3).
* 90 m has 2 significant figures since 1 and 2 are significant (nonzero).
Regards.
Which is the most stable? Carbon (C) Sodium (Na) Helium (He)