Sir Alexander Fleming (6 August 1881 – 11 March 1955) was a Scottish physician and microbiologist, best known for discovering the enzyme lysozyme and the world's first broadly effective antibiotic substance which he named penicillin.
For this discovery he shared the Nobel Prize in Physiology or Medicine in 1945 with Howard Florey and Ernst Boris Chain.
he was a british doctor, born in august 6, 1881. he was also known as pharmacologist.
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Ms. Terries was given a beautiful deep red gem. She knew she might be holding a ruby. Or, she might be holding a stone worth more than rubies, a stone rared than diamonds – a red beryl. Ms. Terries needed to be careful in her calculations. Red Beryl is a mixture of minerals and its density can be anywhere from 2.63g/cm3 to 2.92 g/cm3 Rubies can also vary in density from 3.9 g/cm3 to 4.1 g/cm3. Ms. Terries weighed the stone. It weighed 4.35 g. When put into a graduated cylinder of water, the water level rose 1.5 mL. Determine the density of the gem. Was it ruby or red beryl?
Answer:
red beryl
Explanation:
Red Beryls = Density range is 2.63g/cm3 to 2.92 g/cm3
Rubies = Density Range is 3.9 g/cm3 to 4.1 g/cm3
Mass of stone = 4.35 g
Volume of solid = change in water level = 1.5 mL = 1 cm3
Relationship between mass, volume and density is given by;
Density = Mass / Volume
Density = 4.35 / 1.5 = 2.9 g/cm3
The density of the stone falls in the red beryls range hence it is a red beryl.
How many moles of CO2 are found in 2.5 L of CO2?
Answer: 2.5L x 1mol/22.4 = 0.112 mol
Explanation:
Which of the following correctly describes a proton? Group of answer choices Location: nucleus, contribution to mass: usually about half, charge: positive Location: nucleus, contribution to mass: virtually none, charge: positive Location: outside nucleus, contribution to mass: usually about half, charge: positive Location: nucleus, contribution to mass: usually about half, charge: none
Answer:
Location: nucleus, contribution to mass: usually about half, charge: positive
Explanation:
Protons are a part of the nuclear particles alongside the neutrons. Protons and neutrons are all together called sub-atomic particles and they share the nucleus at the center of an atom together.
Protons carry positive charges. They determine the mass of the atom alongside the neutrons. They contribute half to the mass of an atom and the other part is lies on the mass of a neutron. Neutrons do not carry any charges.HY
Warm
Cool
Is this a land or a sea breeze?
Answer
Explanation:
Recall that the land surface cools quicker than the water surface at night. Therefore, the warmer air over the ocean is buoyant and is rising. The denser cool air over the land is flowing offshore to replenish the buoyant warm air and is called a land breeze.
Base your answers to questions 74 through 76 on the data table below and on your knowledge of Earth
science. The data table shows the mass of a sample of radioactive carbon-14 remaining after each half-life.
Data Table
Number of Half-lives Mass of Carbon-14 (9)
0
64
1
32
2
16
8
3
4
4
5
2
6
1
74 On the grid in your answer booklet, construct a line graph by plotting the data for the mass of carbon-14 in
the sample for each half-life shown on the data table. Connect the plots with a line. [1]
75 Identify the stable disintegration product of the radioactive isotope carbon-14. [1]
76 Determine the number of grams of carbon-14 remaining in this sample at 17,100 years. [1]
Answer:
See explanation
Explanation:
Now we have, the graph attached.the stable disintegration product of C-14 is N-14.
Then;
Since the mass of C-14 originally present is 64g, at a time t= 17100 years, we will have;
N/No = (1/2)^t/t1/2
N = mass of C-14 at time t
No= mass C-14 originally present
t = time taken for N amount of C-14 to remain
No = mass of C-14 originally present
t1/2 = half life of C-14
N/64 = (1/2)^17,100/5730
N/64 = (1/2)^3
N/64 = 1/8
8N = 64
N = 8 g
what is the momentum of a 3 kg bowling ball moving at 3 m/s
Answer:
9 kg.m/sExplanation:
The momentum of an object can be found by using the formula
momentum = mass × velocity
From the question we have
momentum = 3 × 3
We have the final answer as
9 kg.m/sHope this helps you
In plants, algae, and some bacteria, energy is produced by the:
A. nucleus
B. chloroplast
C. vacuole
D. mitochondria
Answer: D?
Explanation: The mitochondrion (plural mitochondria) is a membrane-bound organelle found in the cytoplasm of eukaryotic cells. It is the power house of the cell; it is responsible for cellular respiration and production of (most) ATP in the cell.
Explain why heating a liquid causes it to evaporate more quickly.
Answer:
If a liquid is heated the particles are given more energy and move faster and faster expanding the liquid. The most energetic particles at the surface escape from the surface of the liquid as a vapour as it gets warmer. Liquids evaporate faster as they heat up and more particles have enough energy to break away.
Explanation:
Hey please answer this for me thanks.
Explanation:
Moles of N2 = 84/28 = 3.0mol
Moles of H2 = 29/2 = 14.5mol
Hence amount of ammonia produced = 6.0 * 17 = 102g.
Help me ASAP !!! Thank youuu
Answer:
uhh the first one is the baby plants are gentically simulator to the parent if its wrong im sorry
Explanation:
Mg + 2 AgNO₃ → Mg(NO₃)₂ + 2 Ag How many grams of magnesium nitrate, Mg(NO₃)₂, are formed when 9.87 moles of silver nitrate, AgNO₃, react?
Mass of Magnesium nitrate formed : 731.86 g
Further explanationA reaction coefficient is a number in the chemical formula of a substance involved in the reaction equation. The reaction coefficient is useful for equalizing reagents and products.
Reaction
Mg + 2AgNO₃ → Mg(NO₃)₂ + 2 Ag
moles of silver nitrate, AgNO₃ = 9.87
mole ratio AgNO₃ : Mg(NO₃)₂ = 2 : 1, so mol Mg(NO₃)₂ :
[tex]\tt \dfrac{1}{2}\times 9.87=4.935[/tex]
mass of Mg(NO₃)₂(MW=148,3 g/mol) :
[tex]\tt mass=mol\times MW\\\\mass=4.935\times 148,3\\\\mass=731.86~g[/tex]
Rank the electronegativity values of lithium, oxygen, potassium, and selenium from lowest to highest
Answer:
Potassium < lithium < Selenium < Oxygen
Explanation:
Oxygen has the highest electronegativity value from the given choices.
Electronegativity of an element is a property that combines the ability of its atom to lose and gain electrons.
It is a measure of the relative tendency with which atoms of the element attracts valence electrons in a chemical bond.
Down a group, electronegativity reduces and across the period from left to right, it increasesPotassium and lithium are in group 1 , selenium and oxygen are group 7;
So group 1 elements will have lower electronegativity value.
Potassium is below lithium in group 1 and its electronegativity value will be lower.
Selenium is below oxygen and also, its electronegativity value is lesser.
The electronegativity values of lithium, oxygen, potassium, and selenium from lowest to highest is potassium, lithium, selenium and oxygen.
The electronegativity of an element is a measure of the tendency of an atom of element to attract bonding pair of electrons. Electronegative elements have the ability to attract shared electrons of covalent bonds to itself.
The most electronegative element is fluorine. Electronegativity increases across the period in the periodic table .
Electronegativity decreases down the group in the periodic table. Generally metallic elements are have lower electronegativity. This is because they mostly give out there electrons.
Therefore, the electronegativity values of lithium, oxygen, potassium, and selenium from lowest to highest is potassium, lithium, selenium and oxygen.
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Chlorine has two natural isotopes, chlorine-35 and chlorine-37.
Describe the effect these isotopes have on the relative atomic mass of chlorine
Answer:
The relative atomic mass of chlorine depends on the ratio between the abundance of these two naturally-occurring isotopes.
Explanation:
The relative atomic mass of an element is a weighted average of the atomic mass of its naturally-occurring isotopes. The relative abundance of each isotope gives its weight in this weighted average.
For these two naturally-occurring isotopes of chlorine:
The relative atomic mass of [tex]^{35}{\rm Cl}[/tex] is approximately [tex]34.969[/tex] daltons. The relative abundance of this isotope in nature is approximately [tex]0.758[/tex]. The relative atomic mass [tex]^{37}{\rm Cl}[/tex] is approximately [tex]36.966[/tex] daltons. The relative abundance of this isotope in nature is approximately [tex]0.242[/tex].[tex]\begin{array}{|c|c|c|}\cline{1-3} \text{Isotope} & \text{Atomic Mass} & \text{Relative Abundance}\\ \cline{1-3} ^{35}{\rm Cl} & \approx 34.968\; \rm Da} & \approx 0.758 \\ \cline{1-3} ^{37}{\rm Cl} & \approx 36.966\; \rm Da & \approx 0.242 \\ \cline{1-3}\end{array}[/tex].
[tex]\begin{aligned}&\text{relative atomic mass of Cl} \\ &= \text{atomic mass of $^{35}{\rm Cl}$} \times \text{relative abundance of $^{35}{\rm Cl}$} \\&\quad + \text{atomic mass of $^{37}{\rm Cl}$} \times \text{relative abundance of $^{37}{\rm Cl}$} \\ &\approx 34.968\; \rm Da \times 0.758 + 36.966\; \rm Da \times 0.242 \\ &\approx 35.45\; \rm Da \end{aligned}[/tex].
The relative abundance of [tex]^{35}{\rm Cl}[/tex] is much higher than that of [tex]^{37}{\rm Cl}[/tex]. Consequently, the relative atomic mass of the element [tex]\rm Cl[/tex] is closer to the atomic mass of [tex]^{35}{\rm Cl}\![/tex] than that of [tex]^{37}{\rm Cl}\![/tex].
The structures of three hydrocarbons are given below : a. They have same physical properties. B.They have same structural formula. c.They have same general formula. D.They are isomers of each other.
Answer:
The correct answer is option C "They have same general formula"
Explanation:
Hydrocarbons are any of a class of natural substance intensifies made distinctly out of the components carbon (C) and hydrogen (H). The carbon particles consolidate to shape the structure of the compound, and the hydrogen molecules append to them in various arrangements.
Hydrocarbons are the chief constituents of oil and gaseous petrol. They fill in as powers and ointments just as crude materials for the creation of plastics, strands, rubbers, solvents, explosives, and modern chemical substances.
All of the compounds given are alkanes and they have the same general formula which is represented by CnH2n+2, where ‘n’ is the number of carbon atoms.
What did the Curies conclude about radioactivity based on their studies?
A. The amount of radioactivity is an extensive property because it varies as the amount of material varies.
B. The amount of radioactivity is an extensive property because it remains constant as the amount of material varies.
C. The amount of radioactivity is an intensive property because it varies as the amount of material varies.
D. The amount of radioactivity is an intensive property because it remains constant as the amount of material varies.
Answer:
c
Explanation:
Most metals are _____ at room temperature and generally have moderate to high melting and boiling points because the metallic bond is fairly strong. The melting point of a metal will _____ as atomic size increases because larger metal ions have a _____ attraction for the electron sea.
Answer:
solid
decrease
smaller
Explanation:
f
Help I’ll give brainlist
Answer:
A, And D
Explanation:
I did this before and i got it right ❤
What is the approximate energy of a photon having a frequency of 4 x 10^7 Hz? (h = 6.6 x 10^-34 J . s)
Answer:
2.64 ×[tex]10^{-26}[/tex] J
Explanation:
I think you should mark it a physics question instead but anyway.
---------------------------------------------------------------------------
The Planck equation should be applied:
E = hv , while E is energy of proton; h is Planck constant; and v is frequency.
E = 6.6 × [tex]10^{-34}[/tex] × 4 × [tex]10^{7}[/tex]
= 6.6 × 4 × [tex]10^{-27}[/tex]
= 2.64 ×[tex]10^{-26}[/tex] J
Aluminum has the electronic configuration 2,8,3. How many valence
electrons are in the aluminum atom?
Answer:
3 valence electrons
Explanation:
Because aluminum has three, that means three fluorines can bond. The make the formula AlF3, also known as aluminum trifluoride. Each of the fluorine atoms gets an electron to fill their shell, and the aluminum loses three, giving it a filled shell too (remember, aluminum has three extra electrons).
MARKING BRAINLIEST!
plant or animal and to explain the reasoning for their conclusion. What is the correct response?
The cell is an animal cell because it has a cell membrane and no cell wall. Cell walls are unique to plant cells.
The cell is a plant cell because it has cytoplasm, which helps the plant make their own food from sunlight.
The cell is a plant cell because it has chloroplast, which helps the plant make its own food from sunlight.
The cell is an animal cell because it has chloroplast used for making useable energy.
Answer:
The cell is a plant cell because it has chloroplast, which helps the plant make its own food from sunlight.
Explanation:
Chloroplasts are organelles found in plant cells and eukaryotic algae that conduct photosynthesis. Chloroplasts absorb sunlight and use it in conjunction with water and carbon dioxide gas to produce food for the plant.
How do particles change as the temperature increases in a system? Is this a chemical or physical change?
Answer:
chemical change
Explanation:
particals react to temperature wheteher its cold or warm
The particles begin to move at a higher speed. It is a physical change.
Temperature is defined as the average kinetic energy of the particles of a body. Hence, when a body is heated, the kinetic energy and consequently the speed of its particles increases.
This increase in particle speed is reversed when the system cools down. Recall that a physical change is easily reversible while a chemical change is not easily reversible.
As such, this increase of particle speed with temperature is a physical and not a chemical change.
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How did we find out the nitroglycerin would also help people with weak hearts?
Answer:
The physician William Murrell was one of the first physicians to recognize the the clinical benefits of nitroglycerin in the treatment of the heart disease known as angina pectoris, a type of chest pain caused by reduced blood flow to the heart.
Explanation:
The physician William Murrell was one of the first physicians to recognize the the clinical benefits of nitroglycerin in the treatment of the heart disease known as angina pectoris, a type of chest pain caused by reduced blood flow to the heart. He also used nitroglycerin to treat and reduce high blood pressure. He used small diluted doses of nitroglycerin to treat patients with angina pectoris. Murrell published his treatment results in the article "Nitro-glycerine as a remedy for angina pectoris," in the journal The Lancet in 1879. Thereafter, the use of nitroglycerin as treatment procedure for angina pectoris soon became generally adopted by other physicians.
Nitroglycerin is a vasodilator which is a medicine that opens blood vessels in order to improve blood flow. Nitroglycerine acts to improve blood flow to the heart by opening up or dilating the coronary arteries in the heart, thereby reducing how hard the heart has to work in pumping blood round the body. It reduces preload by dilating veins and reduces afterload moderately by dilating arteries.
Nitroglycerin comes in two forms: quick-acting forms and long-acting forms.
The quick-acting forms include tablets or oral sprays.
Long-acting forms include pills, tablets, skin ointment, and skin patches.
Is combining baking soda and shaving cream a chemical or physical change? It doesn't have to be for today, but please help!
Answer:
it's chemical
Explanation:
materials that prevent the heat to flow call
Answer:
Materials that prevent heat to flow are known as heat insulators.
Explanation:
hope it helps! ฅ'ω'ฅ
2. Vessels that carry blood back to the heart are called
O a. capillaries
b. arteries
O c. veins
O d. both band c
Answer:
the answer for your question is veins
Answer:
blood vessels aka veins
PLEASE HELP!!!!
it would mean alot !
Answer:
i looked it up its slinky waves
Explanation:
Answer:
diffracted
Explanation:
Sure it might look like a slinky but if you're talking about waves then it's deffinetly diffracted hope this helps
Given the equation representing a reaction: H + H --> H2, explain in terms of energy what is happening as the bond is being formed
Answer:
The formation of the bond releases energy. This is because the individual hydrogen atoms are more unstable than when they are joined together. Stability brings about the release of energy, and this would be an exothermic reaction.
How does one determine how much of a molecule is produced in a reaction?
O A. Oxidation states are used to calculate the number of product molecules.
B. The molar masses of the molecules tell how many grams of product will form.
O c. The coefficients and molar masses are used to calculate amounts of molecules
D. The mass of the products is determined by adding the mass of the reactants.
Answer:
c
Explanation:
i doubt it
The coefficients and molar masses are used to calculate the amounts of molecules. Hence, option C is correct.
What is a molecule?The smallest particle of a substance has physical and chemical properties of that substance. Molecules are made up of one or more atoms.
A molecule can be determined by how much is produced in a reaction through the coefficients and molar masses are used to calculate the amounts of molecules.
Hence, option C is correct.
Learn more about molecules here:
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What does one mole of oxygen and one mole of carbon dioxide have in common?
Answer:
Equal number of moles
Explanation:
Thats life
14. Which of the following involves a chemical change?
A.mixing
b. melting
grinding
d. decomposing
Answer:
D. decomposing
General Formulas and Concepts:
Chemistry
Chemical vs Physical ChangesExplanation:
A would be incorrect because mixing 2 things together doesn't necessarily create a chemical change. Take oil and water for example. You can mix the 2 and it would not have a chemical change.
B would be incorrect because you are simplify changing the state of matter of the object. Iron in solid form is still iron in liquid form; there is no chemical change.
C would be incorrect for similar reasons as B. You are simply changing the state of matter.
D would be the remaining and correct answer. Decomposing changes one object into a different one by chemically changing.