A. Acceleration is positive and speed is increasing.
Further explanationThe motion performed by a runner is part of a uniformly accelerated motion with constant acceleration.
Equation used
[tex]\tt \boxed{\bold{v_f=v_i+at}}[/tex]
vf = final velocity
vi = vo = initial velocity
When a runner moves from rest, his speed will increase from being at rest (vi=0) and then move with a constant acceleration(a), and as soon as he crosses the finish line his acceleration will decrease (experience a deceleration ⇒a=- ) and decrease his speed until it finally stops
Velocity and speed are different because velocity itself is a vector quantity that takes into account direction and displacement, while speed is a scalar quantity (only distance).
So the speed does not take positive or negative values because it involves direction, while acceleration takes positive and negative values (deceleration) because it takes direction.
Energy must be removed from a liquid to change it to a solid.
True or false?
Answer: F
Explanation:
Brainlist me
Find the mass, in grams, of 7.50×1024 formula units of aluminum oxide.
Which element (Na or Cl) is more likely to steal an outer electron from the other?
Answer:
Cl is more likely to than Na
Explanation:
The question asks for the element more take up an electron from the other
The ability of an atom to take take or give electrons in a chemical reaction, depends on its electron affinity and ionization energy, respectively
Chlorine, Cl, has the highest electron affinity in the periodic table which makes it attract electrons more towards itself
Sodium, Na, has a low ionization energy (about 2/5 of that of chlorine) than chlorine, Cl, making sodium more readily able to give its valence electron in a reaction
Therefore, Cl is more likely to take up an outer electron from Na.
65 POINTS AND BRAINLIEST PLEASE HELP ASAP
For this assignment, you will write a research essay, or create a presentation, about a scientist who contributed knowledge to the field of chemistry. Your essay, or presentation, should include the following information about your scientist:
Describe your scientist's contributions and innovations to his or her field.
How did your scientist's research and data influence future use of his or her findings?
Describe the background, interests, or goals that affected your scientist's observations and conclusions.
Once you have selected a scientist, you will need to locate at least three different reliable resources to use to conduct your research. You may use textbooks, the Internet, or library books. These resources should be cited within your presentation and should be listed in a bibliography that you submit with your essay, or slide presentation. Use the Citations, Essay Writing, and Finding Reliable Resources tutorials to guide your writing.
If you have another method by which you would like to present your research findings, please have it approved by your instructor before you begin writing. No matter what presentation style you choose, be sure to use complete sentences and paragraphs, and include all of the necessary research required. You should also review the grading rubric before you begin. Select one of the following scientists, or pick another scientist of interest with your instructor's permission, to conduct your research on: Rosalind Franklin
Answer:
Rosalind Elsie Franklin (25 July 1920 – 16 April 1958)was a British biophysicist and X-ray crystallographer who made critical contributions to the understanding of the fine molecular structures of DNA, RNA, viruses, coal and graphite. The DNA work achieved the most fame because DNA (deoxyribonucleic acid) plays essential roles in cell metabolism and genetics, and the discovery of its structure helped scientists understand how genetic information is passed from parents to children.
rosalindfranklin
Franklin is best known for her work on the X-ray diffraction images of DNA which led to discovery of DNA double helix. Her data, according to Francis Crick, was "the data we actually used" to formulate Crick and Watson's 1953 hypothesis regarding the structure of DNA.Franklin's X-ray diffraction image confirming the helical structure of DNA were shown to Watson without her approval or knowledge. Though this image and her accurate interpretation of the data provided valuable insight into the DNA structure, Franklin's scientific contributions to the discovery of the double helix are often overlooked. Unpublished drafts of her papers (written just as she was arranging to leave King's College London) show that she had independently determined the overall B-form of the DNA helix and the location of the phosphate groups on the outside of the structure. However, her work was published third, in the series of three DNA Nature articles, led by the paper of Watson and Crick which only hinted at her contribution to their hypothesis.
After finishing her portion of the DNA work, Franklin led pioneering work on the tobacco mosaic and polio viruses. She died in 1958 at the age of 37 from complications arising from ovarian cancer.
Calculate the energy and frequency of red light having a wavelength of 6.55 x 10⁻7m.
Answer:
E = 3.035× 10-¹⁹J = 1.9eV
f = 4.58 × 10¹⁴Hz
Explanation:
wavelength = 6.55 × 10-⁷m
c = 3 × 10⁸m/s
f = ?
E = ?
a) f = c/wavelength
f = 3 × 10⁸/6.55 × 10-⁷
f = 4.58 × 10¹⁴Hz
b) E = hc/wavelength
E = 6.626×10-³⁴ × 3 × 10⁸/ 6.55 × 10-⁷
E = 3.035 × 10-¹⁹J
1ev = 1.6 × 10-¹⁹J
Therefore E = 3.035/1.6 = 1.9eV
Wasim and his friends want to test if the solution of a substance is acidic or not. These are the tests that each of them performed. Wasim: Dipped the blue litmus in the solution Akram: Dipped the red litmus in the solution Neha: Dipped both the blue and the red litmus in the solution one after other. Who among them performed a proper test ?
Answer:
Wasim and Nehra did the Proper testing
Explanation:
In acidic condition Blue litmus turns red
In basic condition Red litmus turns Blue
In order to test an Acidic solution we need Blue litmus.
Wasim Dipped the blue litmus in the solution : it will turn red and shows acid
Akram Dipped the red litmus in the solution : No it will not show, it's a test for base
Neha: Dipped both the blue and the red litmus in the solution one after other.
Blue litmus will turn red which will show Acidic nature, after that Adding Red litmus in it will not show any change as Red litmus only changes in Basic condition.
Therefore, Wasim and Nehra did the Proper testing
how do the mass and height of an object affect the gravitational potential energy?
A. height has great a greater effect than mass gravitational potential energy
B. mass and height have the same effect on gravitational potential energy.
C. height has almost 10 times the effect on gravitational potential energy then mass has.
D. Mass has a greater effect than height on gravitational potential energy.
Answer:
B. mass and height have the same effect on gravitational potential energy.
Explanation:
Both mass and height have the same effect on the gravitational potential energy of body.
Gravitational potential energy is the energy of a body due to that of another body. It usually the energy at rest in a body.
It is mathematically expressed as;
G.P.E = m x g x h
m is the mass
g is the acceleration due to gravity
h is the height
We see that both the height and mass are directly proportional to the gravitational potential energy and as such, they have the same effect.
How many valence electrons are found in atoms of group 14?
Answer:
4 valence electrons.
Explanation:
A book is sitting on a desk. The area of contact between the book and the desk is 0.06 m2 of the body's weight is 30 N what is the pressure the book exerts on the desk
Answer:
500N/m²
Explanation:
The Pressure can be calculated using the formula:
P = F/A
Where;
F = force (N)
A = Area (m²)
Based on the information provided in the question, F = 30N, A = 0.06m²
P = F/A
P = 30/0.06
P = 500N/m²
1. The speed limit on most city streets is (25 miles). How many meters per minute
hour
is this?
This is a conversion.
Answer:
[tex]Speed = 670.56 \frac{m}{min}[/tex]
Explanation:
Given
[tex]Speed = \frac{25 mi}{hr}[/tex]
Required
Convert to meters per minutes
[tex]Speed = \frac{25 mi}{hr}[/tex]
Start by converting the speed from miles to meters
[tex]1\ mile = 1609.34\ meters.[/tex]
So, we have:
[tex]Speed = \frac{25 * 1609.34\ m}{hr}[/tex]
[tex]Speed = \frac{40233.5\ m}{hr}[/tex]
Next, we convert time from hours to minutes
[tex]1\ hour = 60\ minutes[/tex]
So, we have:
[tex]Speed = \frac{40233.5\ m}{60\ min}[/tex]
[tex]Speed = 670.56 \frac{m}{min}[/tex]
Hence, the equivalent of 25 miles per hour is 670.56 meters per minutes
Which equation is balanced?
Mg3N2 + H2O 3MgO + 2NH3
C3H8 + 5O2 H2O + 3CO2
Zn + 2HCl ZnCl2 + H2
3H2SO4 + 2Fe Fe2(SO4)3 + H2
Answer:
it's the third one
Explanation:
in the first one oxygen molecules aren't balanced
the second ok me oxygen isnt balanced
and the fourth one hydrogen isn't balanced
hope it helps ;)
A balanced equation is a representation in which the coefficients of the individual atoms of a molecule or compound are the same on both the left and right of the equation.
The correct answer is:
Option C. Zn + 2 HCl --------> ZnCl₂ + H₂
This can be explained as:
In the first equation, the number of H and O atoms are not balanced.In the second case, the atoms of hydrogen and oxygen are not the same on the sides of the equation.In the third reaction between zinc and hydrochloric acid, all the atoms of the reaction are balanced.In the fourth reaction, the hydrogen atoms are not balanced.Therefore zinc and hydrochloric acid reaction are balanced.
To learn more about balancing the reactions follow the link:
https://brainly.com/question/14263388
How many moles of Fe are produced from 7 moles of Zn?
Zn(s) + FeSO4(aq) → ZnSO4(aq) + Fe(s)
Answer:
7 mol Fe
General Formulas and Concepts:
Chemistry
StoichiometryExplanation:
Step 1: Define
RxN: Zn (s) + FeSO₄ (aq) → ZnSO₄ (aq) + Fe (s)
Given: 7 moles Zn
Step 2: Stoichiometry
[tex]7 \ mol \ Zn(\frac{1 \ mol \ Fe}{1 \ mol \ Zn} )[/tex] = 7 mol Fe
Step 3: Check
We are given 1 sig fig.
Since our final answer is in 1 sig fig, there is no need to round.
While making chicken soup for his family one evening, Luis added the amount of salt the recipe called for. After tasting the soup, he decided the seasoning was correct. He then he let the chicken soup simmer for two hours to blend the flavors. But when he served the soup, it was too salty. What happened to the soup to make it so salty?
A. He added to much solvent
B. He added something else besides salt
C. Some of the chicken was saltier than the rest of it
D. Some water evaporated and concentrated the salt
Answer:
D
Explanation:
Which is bigger an atom or a cell?
Answer:
Both are small
Explanation:
Atom comprises to die molecules, and cell comprise to for tissues
How does an atom become charged?
-How does an atom get a positive charge?
-How does an atom get a negative charge?
-Can an atom get a charge with a change of particles in
the nucleus? Explain, please.
Answer:
An atom becomes charged when there is an unequal amount of positive and negative particles in the nucleus.
An atom gets a positive charge when there is an increase in protons or a decrease in electrons, such that there are more protons than electrons in the nucleus.
An atom gets a negative charge when there is an increase in electrons or a decrease in protons, such that there are more electrons than protons in the nucleus.
An atom can get a charge with a change of particles in the nucleus if that change results in an uneven number of protons and electrons.
Explanation:
Because protons are positively charged particles and electrons are negatively charged particles, a neutral atom has an equal amount of protons and electrons, so that the opposite charges of the particles cancel each other out.
However, if there is an unequal amount of protons or electrons in the nucleus, the charge of the particles will no longer be canceled out, and the atom as a whole will take on a positive or negative charge.
Which type of weathering has the greatest impact in areas with warm climates and lots of rainfall?
Answer:
In general, hot wet climates accelerate chemical weathering while cold dry climates accelerate physical weathering. Although the rate of weathering depends on the type of rock, rocks in tropical climates experience the highest rates of weathering because of the combination of high heat and heavy rainfall.
Study the image.
A world map showing the Principal World Air Masses. The four major types of air masses are noted on the map.
Which air mass has formed immediately north of Antarctica in the image?
Answer:
a
Explanation:
A world map showing the Principal World Air Masses. The four major types of air masses are noted on the map. The maritime polar has formed immediately north of Antarctica in the image.
Where is the maritime polar formed?The north Pacific Ocean produces the majority of the maritime polar air masses that affect the United States. However, maritime polar air occasionally forms in the North Atlantic Ocean and moves into the New England states.
In the winter, for example, an arctic air mass can move over the ocean, picking up some warmth and moisture from the warmer ocean and transforming into a maritime polar air mass (mP), which is still fairly cold but contains moisture.
In the image, the maritime polar has formed immediately north of Antarctica. The temperature of mP air varies between just above freezing and below 70 degrees Fahrenheit. As it moves over elevated terrain, mP air changes. Mountain ranges on the windward side
Thus, The maritime polar has formed immediately north of Antarctica in the image.
To learn more about the maritime polar, follow the link;
https://brainly.com/question/7423218
#SPJ6
Ice sheets once covered the upper northeastern portion of the United States.
True or False?
Answer:
I do believe the answer is false.
Hope This Helps!!
A packaging engineer is designing a container to hold hydrogen peroxide. The engineer knows that light speeds up the chemical reaction that
changes hydrogen peroxide into oxygen and water. How might the engineer use
that information when designing the container?
It’s science *
The two gases, H2 and O2, were allowed to effuse under the same conditions through a pinhole. If the rate of effusion of O2 was 4.80 x 10-2 ms-1, what is the rate of effusion of H2?
The rate of effusion of H₂ : 7.2 x 10⁻² m/s
Further explanationGraham's law: the rate of effusion of a gas is inversely proportional to the square root of its molar masses or
the effusion rates of two gases = the square root of the inverse of their molar masses:
[tex]\rm \dfrac{r_1}{r_2}=\sqrt{\dfrac{M_2}{M_1} }[/tex]
or
[tex]\rm M_1\times r_1^2=M_2\times r_2^2[/tex]
MW₁ O₂ = 32 g/mol
MW₂ H₂ = 2 g/mol
[tex]\tt \dfrac{1.8\times 10^{-2}}{r_2}=\sqrt{\dfrac{2}{32} }\\\\\dfrac{(1.8\times 10^{-2})^2}{r_2^2}=\dfrac{2}{32}\\\\r_2=0.072=7.2\times 10^{-2}~m/s[/tex]
Options are:
1. 4
2. 8
3. 2
4. 1
Answer:
1. 4
Explanation:
there are four atoms of hydrogen. you can tell because there is a 4 after the H.
the oxidation of glucose by enzymes gives
Answer:
Carbondioxide, water and ATP
Explanation:
The reaction is called aerobic respiration because oxygen from the air is needed for it to work.
A solution containing 15.2 g of BaBr2 is reacted with a solution containing excess Na3PO4 to form 9.50 g of precipitate. What is the percent yield of the reaction?
Answer:
Explanation:
3BaBr₂ + 2Na₃PO₄ = 6BaBr + Ba₃(PO₄)₂ (s)
3 x 297 = 891 gm 1 x 602 = 602 gm
891 gram of BaBr₂ yields 602 gram of precipitate
15.2 gram of BaBr₂ yields 602 x 15.2 / 891 gram of precipitate
= 10.23 gram
actual yield = 9.5 gram
percent yield = 9.5 x 100 / 10.23
= 92.86 % .
please i need the answer im dying here ;-
What happens when matter changes state? (choose one from the following :))
Its chemical properties change.
Its physical properties change.
The energy of its particles remains the same.
none of the above
Answer:
anawer is none of the above
Answer:
i think none of the above is the answer
Increasing temperature increases the number of collisions and the potential energy of the colliding molecules and
decreases the reaction rate.
True or False PLZ HELP!!
Can you help me please lol
Answer: Yes
Explanation:
(h) Bohr stated that the energy of the electron is quantised. What does this mean?
Explanation:
It suggests that the extranuclear part consists of electrons in specific spherical orbits around the nucleus.
The concept is based on the premise that the electrons move round the nucleus in certain permissible orbits or energy levels. The ground state is the lowest energy state available to the electrons. It is the most stable state. The excited state is any higher energy level than the ground state. An electron in an energy level has a definite amount of energy associated with it at that level. The electron can undergo transitions from one level to another. This way energy of an electron is quantized to each level.What is the chemical formula for the name lithium fluoride?
Answer: Lithium fluoride is an inorganic compound with the chemical formula LiF.
Answer:
The chemical formula for lithium fluoride is LiF. I hope this helps
(11) su pilate
The substance which is most suitable for drying ammonia is
Answer:mark as brainliest
Explanation:H2SO4 and anhydrous calcium chloride CaCl2 are not used to dry ammonia because they react with it. The gas is passed through fresh quicklime (solid calcium oxide lumps) to effectively dry it.
Which of the following is an example of a chemical change?
A. Sugar Dissolving
B. Eggs frying
C. Ice melting
D. Flour and salt being mixed together
Answer:
Eggs Frying
Explanation:
;)