salks vaccine trail was a double-blind experiment true or false

Answers

Answer 1

Answer:

true

Explanation:


Related Questions

What type of energy is transmitted from the Sun to Earth through space?

Answers

Answer:

solar energy

Explanation:

What is another name for a row on the periodic table?
Answer choices :
Group
Period
Family
Transition Metals

Answers

The answer is period

d) velocity ratio =_________ Iload distance​

Answers

Answer:

velocity ratio is defined as the ratio of distance moved by effort and load in the same time interval

Explanation:

Which will diffuse the most? The particles with the
A. Least potential energy.
B. Most potential energy.
C. Least kinetic energy.
D. Most kinetic energy.

Answers

Answer:

B. Most potential energy

Explanation:

brainest plz

2. DETERMINE THE TEMPERATURE AT
WHICH NIO GRAMS OF POTASSIUM
NITRATE DISSOLVE IN 100 GRAMS OF
WATER

Answers

Answer:

20 degrees Celsius

Explanation:

Atoms and elements are examples of A. molecules. B. mixtures. C. compounds. D. pure substances.

Answers

Answer:

atom are very tiny partical

The chemical formula for the ionic compound aluminum sulfite is Al2(SO3)3. Explain why there are 2 cations for every 3 anions in this compound.

Answers

my mom !!!Explanation:

Musscle man

Liquid or solid water that falls to the ground is called

Answers

Precipitation is water released from clouds in the form of rain, freezing rain, sleet, snow, or hail. It is the primary connection in the water cycle that provides for the delivery of atmospheric water to the Earth. Most precipitation falls as rain.

Which process describes the wearing
away of rock?
A. drainage
B. erosion
C. infiltration
D. weathering

Answers

Answer:

weathering

Explanation:

hope this helps

19. Luke wants to create an aqueous solution that conducts electricity. Which of the following compounds should
he use?
a) KNO3
b) C12H22O11
c) C2H5OH
d) NH4OH

Answers

Answer:

I think b) C12H22O11.

Hope this answer is helpful for u.

a metal worker uses a cutting torch that operates by reacting acetylene gas, C2H2(g), with oxygen gas, O2(g), as shown in the unbalanced equation below: C2H2(g)=O2(g)= CO2(g) = H2O(g) = heat determine the mass of 25 moles of acetylene (gram-formula mass = 26 g/mol

Answers

Answer:

650 grams

Explanation:

Given that acetylene gas reacts with oxygen to produce caobon dioxide, water and heat and the unbalnced equation is

[tex]C_2H_2(g)+O_2(g) \rightarrow CO_2(g) + H_2O(g)+ heat[/tex]

Gram-formula mass of [tex]C_2H_2= 26[/tex] g/mol

So, mass of 1 mole of acelylene is 26 grams

Therefore, mass of 25 moles of acelylene=25x26=650 grams

Hence, the mass of 25 moles of acelylene is 650 grams

The mass of 25 moles of acetylene has been 0.65 kg.

Moles are the count of a number of molecules in an entity and the mass based on the formula mass. 1 mole of a substance has [tex]\rm 6.023\;\times\;10^2^3[/tex] molecules.

The moles can be calculated as:

Moles = [tex]\rm \dfrac{weight}{molecular\;weight}[/tex]

Given, mole of acetylene = 25 mol

molecular mass of acetylene = 26 g/mol

Mass of acetylene = moles [tex]\times[/tex] molecular weight

Mass of acetylene = 25 [tex]\times[/tex] 26

Mass of acetylene = 650 grams

1000 grams = 1 kg

650 grams = 0.65 kg.

The mass of 25 moles of acetylene has been 0.65 kg.

For more information about the mass, refer to the link:

https://brainly.com/question/18838161

Which liquid has the weakest intermolecular forces?

Answers

Answer:

Oil- Only London Dispersion Forces (the weakest intermolecular force)

Water- London Dispersion, Dipole-Dipole, and Hydrogen Bonding

1. An element is defined by the number of:
Electrons
Protons
Neutrons
Chemical Bonds
lons

Answers

Answer:

The correct answer for this question would be B) Protons

Explanation:

I got it right on my test (Can I have brainlyest)

What constitutes a solar system?

Answers

The Solar System may be divided by its components into three major regions: the inner system, the near outer system, and the far outer system. The near outer system might also be referred to as the middle system.

Our solar system consists of our star, the Sun, and everything bound to it by gravity — the planets Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune, dwarf planets such as Pluto, dozens of moons and millions of asteroids, comets and meteoroids.
Goodluck my friend!!

An aluminum isotope consists of 13 protons, 13 electrons, and 14 neutrons. What is its mass number? *

Answers

Answer:

26.981539

Explanation:

In mitosis, how does a daughter cell compare with its parent cell?
A.
A daughter cell has twice as many chromosomes as its parent cell.
B.
A daughter cell has half as many chromosomes as its parent cell.
C.
A daughter cell and its parent cell are exact copies of each other.
D.
A daughter cell has no similarity to its parent cell.

Answers

Answer: im pretty sure its the last (one daughter cell has no similarity to its parent cell.)

Explanation: bc a daughter cell has 30 and the parent cell would have 46 and thats not twice or half as many and they arent the same either so the last one makes sences  

In the reaction 2AgI + Na2S → Ag2S +2NaI, calculate the number of moles of AgI needed to react with 85.0 g

Answers

Answer:

8.5gNaI × 1molNaI/78gNaI × 234.7g AgI / 1 MOL AgI × 2Mol Ag I / 1mol Na2S=51.2 g of AgI reacts with Na2 S

Explanation:

conversion factor is used to make sure that all the units cancels with the other units and we only remain with the mass of Ag I which is 51.2g but since the number of moles can be calculated by dividing with the relative molecular mass therefore 51.2g/234.7gmol=0.22mol

Which one has more Thermal Energy? A cup of boiling water or a bathtub of warm water? Explain! Please answer if you can, thank you!! P.S this is science but i just put it as chemistry?

Answers

Answer:

See explanation

Explanation:

The thermal energy of a substance is affected both by its mass and by its temperature. Thermal energy is defined as the total kinetic energy of all particles in an object.

Even though the cup of water has a higher temperature, the bathtub has more thermal energy because it contains much more mass of water compared to the cup. It will release more thermal energy to the surroundings compared to the cup of boiling water.

The bathtub of warm water has a higher total thermal energy due to its bigger volume, but the cup of boiling water has a higher average kinetic energy per particle.

The thermal energy of a cup of boiling water is greater than that of a warm bathtub. The sum of all the kinetic energies of the particles in a substance is its thermal energy. The temperature of boiling water is higher than that of warm bathwater. The average kinetic energy of the particles is measured by temperature. The average kinetic energy of the particles in a cup of boiling water would be higher than that of the warm water in a bathtub, which is normally between 38 and 45 degrees Celsius (100 and 113 degrees Fahrenheit), because water has a boiling temperature of 100 degrees Celsius (212 degrees Fahrenheit).

To know more about thermal energy, here:

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Someone please help will mark as brainliest

Answers

1. solute is the substance that is being dissolve,while solvent is dissolving medium

2.saturated is solution that contain maximum amount of solut that capable of being dissolve and supersaturated is solution that contain less amount or medium of solut that capable being dissolve : example vinger

3. is a number placed in front of a chemical symbol or formula. It shows how many atoms or molecules of the substance are involved in the reaction. For example, two molecules of hydrogen would be written as 2 H2, and two molecules of water would be written 2 H2O . yes it's can be change only in caseWhen you balance an equation you can only change the coefficients

What type of reaction will occur with the following reactants?

CaS + NaCl -->

A) double replacement
B) decomposition
C) synthesis
D) single replacement

Answers

Answer:

A) double replacement

Explanation:

Chemical equation:

NaCl +CaS    →    Na₂S + CaCl₂

Balanced chemical equation:

2NaCl +CaS    →    Na₂S + CaCl₂

The given reaction is double replacement reaction in which cation and anions of each reactant exchange with each other.

Double replacement:

It is the reaction in which two compound exchange their ions and form new compounds.

AB + CD → AD +CB

Other options are incorrect because,

Synthesis reaction:

It is the reaction in which two or more simple substance react to give one or more complex product.

AB → A + B

Single replacement:

It is the reaction in which one elements replace the other element in compound.

AB + C → AC + B

Decomposition reaction:

It is the reaction in which one reactant is break down into two or more product.

AB → A + B

ILL MARK BRAINLIEST NEED HELP ASAP

THE OTHER TWO ANSWER CHOICES WERE

20

40

Answers

the first table goes with 20
the second table goes with 40
the third table goes with .2
the fourth table goes with .6

hope this helps!!

Which is a component of John Dalton’s atomic theory?
The ratio of atoms in a compound is fixed.
The atoms of different elements are the same.
An atom is a small particle of matter that can be broken down.
A reaction can create or destroy atoms as well as rearrange them.

Answers

Answer: lol the answer is A

Explanation:

i’m just smart like that , thought i should give y’all a clue

Answer:

The ratio of atoms in a compound is fixed.

Explanation:

its a

Consider the following reaction: 3Fe(s) + 4H₂O(g) ➞ Fe₃O₄(s) + 4H₂(g). To answer the following question: "How many moles of hot water vapor (steam) must react to produce 275 g of Fe₃O₄?" How many steps will it take to get the answer? *
4 points
1
2
3
4

Answers

Answer: 2

Explanation:

To calculate the moles :

[tex]\text{Moles of solute}=\frac{\text{given mass}}{\text{Molar Mass}}[/tex]

[tex]\text{Moles of} Fe_3O_4=\frac{275g}{233.5g/mol}=1.18moles[/tex]

[tex]3Fe(s)+4H_2O(g)\rightarrow Fe_3O_4(s)+4H_2(g)[/tex]  

According to stoichiometry :

1 mole of [tex]Fe_3O_4[/tex] are produced by = 4 moles of [tex]H_2O[/tex]

Thus 1.18 moles of [tex]Fe_3O_4[/tex] will be produced by=[tex]\frac{4}{1}\times 1.18=4.72moles[/tex]  of [tex]H_2O[/tex]

Mass of [tex]H_2O=moles\times {\text {Molar mass}}=4.72moles\times 18g/mol=85.0g[/tex]

Thus 85.0  g of [tex]H_2O[/tex] will be required and 2 steps are required to get the answer.

what mining biodivirsity​

Answers

Answer:

Explanation:

Mining affects biodiversity at multiple spatial scales (site, landscape, regional and global) through direct (i.e. mineral extraction) and indirect processes (via industries supporting mining operations, and external stakeholders who gain access to biodiversity-rich areas as the result of mining).

What is the different between stereotyping someone and judging them? paragraph in length please

Answers

Answer:

Stereotyping provides humans with the ability to quickly sort out patterns in a randomly diverse world filled with people of every size, shape, gender, age, color, and sexual orientation. And it’s just a quick first pass, nothing more

at the left.
6.
1. Work equals
A force x distance
B. force - distance
C. force + distance.
The force you apply to a machine
is the
A. input force.
B. output force.
C. efficiency.
2.
The unit of work is the
A. watt.
B. newton.
C. joule.
7.
The efficiency of all real
machines is
A. greater than 100%
B. equal to 100%
C. less than 100%
3.
Power is the amount of
A. work done per unit of time.
B. force on a certain area.
C. pressure in a volume of liquid.
8.
4.
The unit for power is the
A. joule.
B. Meter per second
C. watt.
The fixed point that a lever rotates
around is called the
A. fulcrum.
B. input force.
C. wedge.
9.
5.
A machine cannot change the
A. direction of the input force.
B. amount of work needed to do
A screwdriver is an example of a
simple machine called a
A. pulley.
B. screw
C. wheel and axle.
a task.
C. distance over which a force
is applied
10.
Your front teeth are
A. wedges.
B. levers.
C. compound machines.

Answers

Answer:

i know right answer

Explanation:

let me explain

Please answer correctly !!!!!!!!!!!!!!! Will mark brainliest !!!!!!!!!!!!!!!!!!!!

Answers

Answer:

i dont have an answer for sure because it doesnt specify WHAT its energy chang occurs but i think its physical change

Explanation:

Physical changes only change the appearance of a substance, not its chemical composition. Chemical changes cause a substance to change into an entirely substance with a new chemical formula. Chemical changes are also known as chemical reactions.

examples of chemical change:

burning a fire

boiling an egg

digestion

examples of physical change:

melting ice

rusting

breaking a pencil

hope i helped!!

A cylinder, with a piston pressing down with a constant pressure, is filled with 2.10 moles of a gas (n1), and its volume is 46.0 L (V1). If 0.700 mole of gas leak out, and the pressure and temperature remain the same, what is the final volume of the gas inside the cylinder?

Answers

Answer:

The volume is  [tex]V_2 =15.33 \ L[/tex]

Explanation:

From the question we are told that

    The number of moles of the gas is  [tex]n_1 = 2.10 \ moles[/tex]

      The volume of the gas is  [tex]V = 46.0 \ L[/tex]

        The  of moles of the gas that leaked is  [tex]n_2 = 0.700 \ mol[/tex]

Generally from the ideal gas law

      [tex]PV = nRT[/tex]        

Generally at constant pressure and temperature

        [tex]\frac{V}{n} = constant[/tex]

So   [tex]\frac{V_1 }{n_1} = \frac{V_2 }{n_2}[/tex]

=>    [tex]V_2 = \frac{ V_1 * n_2 }{ n_1}[/tex]

=>    [tex]V_2 = \frac{ 46.0 * 0.700 }{ 2.10 }[/tex]  

=>    [tex]V_2 =15.33 \ L[/tex]

             

     

Which statement best explains what happens to a leaf when it has lost much-needed water?

Answers

Answer:

its turgor pressure decreases

Explanation: This is also important because this function regulates water loss within the plant. Lower turgor pressure can mean that the cell has a low water concentration and closing the stomata would help to preserve water. :-)

When a leaf loses much-needed water, its turgor pressure would decrease. Hence Option A is Correct

What is Turgor pressure ?

Turgor Pressure is created in the cells of a leaf when there is enough water. The water stretches the cell membrane outward, creating a kind of pressure.

When the cells lose water, the cell membrane shrinks inward and loses the supporting pressure.

Thus, the turgor pressure created by the presence of water is lost by the absence of water.

The absence of water also affects the rate of photosynthesis and transpiration negatively and not positively. A leaf losing water has no bearing on the atmospheric pressure.

learn More about turgor pressure here:

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Part A Read each sentence. Write the letter of the correct answer on the line.
1. Which of the following would result in a chemical change?
A boiling water
C tearing paper
B burning wood
D melting wax

Answers

Boiling water because it’s more obvious
Buring wood is the answer to that question
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