1. 4 significant numbers
2. 6 significant numbers
3. 3 significant numbers
4. 3 significant numbers
Further ExplanationSignificant numbers are numbers obtained from the measurement results of exact numbers and the last number estimated
1. 19.99
all non-zero numbers are significant numbers , so there are 4 significant numbers
2. 140486
a zero which is located between two non-zero numbers including a significant number , so there are 6 significant numbers
3. 0.0609
a zero in front of a decimal point is not a significant number, so there are 3 significant numbers (6,0 and 9)
4. 5.08
Any zeros between two non-zero numbers are significant, so there are 3 significant numbers(5,0 and 8)
how many grams of potassium nitrate are required to prepare 3.00 x 10^2 mL of 0.750 M solution
Answer:
Mass = 22.725 g
Explanation:
Given data:
Mass of potassium nitrate required = ?
Volume of solution = 3.00 ×10² mL
Molarity of solution = 0.750 M
Solution:
Formula:
Molarity = number of moles of solute / L of solution
Now we will convert the volume into L.
3.00 ×10² mL × 1L /1000 mL
0.003 ×10² L or 0.3 L
now we will put the values in formula.
0.750 M = n / 0.3 L
n = 0.750 M × 0.3 L
M = mol/L
n = 0.225 mol
Mass of potassium nitrate:
Mass = number of moles × molar mass
Mass = 0.225 mol × 101 g/mol
Mass = 22.725 g
Where dose the energy that powers the water cycle come from?
Answer:
sun is the energy that powers the water cycle from
is it possible to have a negative ion in a hydrogen atom in real life? Explain.
Answer:
Yes
Explanation:
Abstract. The negative ion of hydrogen continues to be important in atomic physics and astrophysics. Correlations between the two electrons are strong alieady in the ground state, the only bound state in this three-body system.
Which of the following is a physical blend of two or more substances with uniform composition? Select all that apply.
A. Homogeneous mixture
B. Heterogeneous mixture
C. Solution
D. Pure substance
Answer:
homogeneous mixture
Explanation:
A homogeneous mixture and Solution are the physical blend of two or more substances with uniform composition. Thus, options A and C are true.
What do you mean by Mixture?“Mixture is an act of combining two or more chemical substances that are not chemically linked.”
Types of mixtures –
There are two main types of mixture.
Homogeneous Mixture –
A Homogeneous Mixture is a mixture in which composition is uniform throughout the mixture, and it appears like a single substance.
Example – Air is a homogeneous mixture of gas etc.
Heterogeneous mixture –
A Heterogeneous mixture is a mixture in which composition is not uniform throughout the mixture.
Example – Vegetable soup is a heterogeneous mixture etc.
Solution –
A Solution is a homogeneous mixture of two or more solutes dissolved in a solvent.
Example – Solution of sugar in water etc.
Thus, a homogeneous mixture and solution are the physical blends of two or more substances with uniform composition. Thus, options A and C are true.
To learn more about mixture, refer to the below link:
https://brainly.com/question/17344599
#SPJ2
A scientist heats a 300-g sample of iron from 30°C to 50°C. How much heat did the iron absorb.
The specific heat capacity of iron is 0.45 J/gºC.
Оа
Oь
Ос
Od
3,000)
2,700)
202,500)
2,500)
Answer:
d
Explanation:educated guess
how many of protien consumed by humans around the world is fish?
a) 5 percent
b)20percent
c)4p percent
d)50 percent
The answer would be 20% (B)
pls help asap !! unsure how to do this
The Rocky Mountains run parallel to the western coast of the United States. While parts of the California coast are lush and tropical, the area just east of the mountain range is a dry desert. What BEST explains the drastic climate difference between these two adjacent areas?
Answer:
The mountains cause rainfall.
Explanation:
The fact that the mountains run parallel to the coast is the key in the difference in climate between the two areas. Since they are parallel to the sea, they block the wind and moisture coming from the sea towards the land, the mountains cause this air to rise and when it hits the cold air at higher altitudes, it results in rain. This leads to the lush and tropical areas whereas without the parallel mountains to the coast, the amount of rain the area receives decreases, resulting in a desert like environment.
I hope this answer helps.
sketch a heating curve for water at 101kPa
using the information from the phase diagram. Label the melting point and
boiling point temperatures on your heating curve
Answer:
Please find attached a sketch of the heating curve of water at atmospheric pressure ( approximately 101 kPa) as traced from an online source
Explanation:
Given that the pressure at 101 kPa is approximately 1 atmosphere, we have;
The melting point and the boiling point occurs at approximately 0°C and approximately 100°C, respectively;
The melting point and the boiling point experience latent heat, therefore that temperature remains the same, though heat is continuously added
Also, given that the latent heat of vaporization (22.6 × 10⁵ J/kg) is approximately 7 times the latent heat of fusion is (3.33 × 10⁵ J/kg), the length of the plateau representing evaporation would be approximately 7 times longer than the length representing fusion.
The heating curve obtained from an online source for water at atmospheric pressure, is presented in the attached sketch.
Predict the effect of a mutation which limits the production of pigment in hair
Answer:
E
Explanation:
Predict the effect of a mutation which limits the production of pigment in hair
The animal would have white hair or hair with no color.
The animal would have light brown hair.
The animal would have black hair.
The animal would have no hair at all.
The animal would have white hair or hair with no color is the effect of a mutation which limits the production of pigment in hair.
Mutation is the change in the genetic composition of the gene or genetic material which alters the normal functioning of the gene or the genetic material. In the given situation if the mutation occurs at the gene which is responsible for the production of protein pigment responsible for imparting color to the hair. Then it is expected that the gene does not encode for a protein pigment as a result the hair will remain without color or white.Hence, the animal would have white hair or hair with no color is the correct option.
Learn more about mutation:
https://brainly.com/question/3523174
A volume is measured experimentally as
4.09 mL. What is the percent error, given
that the correct value is 4.13 mL?
Answer in units of %.
Answer:
The answer is 0.97 %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 volume = 4.13 mL
error = 4.13 - 4.09 = 0.04
We have
[tex]p(\%) = \frac{0.04}{4.13} \times 100 \\ = 0.968523002...[/tex]
We have the final answer as
0.97 %Hope this helps you
Which element will be more reactive - Mg (magnesium) OR Se (Selenium)? *
Answer:
magnesium
Explanation:
magnesium is in Group 2, in the periodic table. this means that it has 2 valence electrons. the less valence electrons an element or atom has, the more reactive. Selenium has 6 valence electrons. as a result, Mg is more reactive
Recall all the models you described in task 1. Think about the results each model would predict for Rutherford's experiment. Which atomic models does Rutherford's experimental evidence support? Explain why these models are compatible with the experimental results.
The question is incomplete; the complete question is:
Recall all the atomic models you described in task 1. think about the results...
Recall all the atomic models you described in task 1. think about the results each model would predict for rutherford’s gold foil experiment. which atomic models does rutherford’s experimental evidence support? explain why these models are compatible with the experimental results.
the models in task 1 were dalton's, thomson's, rutherford's, and bohr's.
Answer:
Bohr's
Explanation:
Rutherford's theory laid the foundation upon which Bohr's model is founded. Rutherford established the fact that at the center of the atom, there is a nucleus whose radius is smaller than the radius of the atom. This nucleus is positively charged and most of the mass of the atom is concentrated there. Electrons move round this nucleus in orbits.
The experimental evidences of the Bohr's model shows that Rutherford's model was fundamentally correct. However, Bohr's model introduced the idea of quantization of the energy of electrons in an atom. The model went further to explain the spectra lines of the hydrogen atom.
Convert 20 cals to J
Answer: 83.68 J
Explanation:
1 cal=4.184 J
1×20=4.184×20
20cals=83.68 J
All matter has a distinct melting and boiling point that we can use to describe it. Look at these thermometers. They show the temperatures at which each type of matter change from solid to liquid to gas. Use these thermometers to answer the questions on this worksheet.Preview the document
Answer:
Química orgánica
Explanation:
Who uses petroleum and for what purpose?
Answer:
today, petroleum is mostly used as a source of energy, being rich in combustible carbon in the production of electricity or running some sorts of heat engines. ... Raw petroleum (also known as crude oil) is used in three major ways: Transportation, Electricity Generation, and Material Production.
Explanation:
hope it helps!!!!!!!!!!!!!!!!!!!!!!!!!!
In 1897, Joseph Thomson discovered that atoms contained electrons. He proposed a change in the atomic theory of that time, and the theory was modified because of his discovery. Since Thomson's discovery, atomic theory has been further modified. What is the best explanation for why scientific theories are modified?
Answer:
because it is a theory
Explanation:
The best explanation for why scientific theories are modified is simply because it is a theory. Theories are created as a set of suppositions that help humanity understand something that would otherwise be unexplainable. Since they are not proven through scientific facts but instead are more of ideas that help further our understanding of a phenomenon, they tend to be modified as new ideas are introduced and others are proven to be false/wrong.
Which is one precaution to take when working with heat and fire?
Do not use during experiments.
Keep flammables away.
Avoid touching face and eyes.
Do not mix chemicals unless told to do so.
Which rule or principle does this violate?
A. Aufbau Principle
B. Pauli Exclusion Principle
C. Hunds rule
Answer:
Hunds rule is violated here.
Hunds rule : pairing of electrons takes place only if all the orbitals are filled with single electrons each.
A sample of 4.0 mol of neon gas at a pressure of 2.5 atm is injected into a container at
25°C. What is the volume of the container?
Answer:
The volume of container is 39.14 L.
Explanation:
Given data:
Number of moles of neon = 4.0 mol
Pressure of gas = 2.5 atm
Temperature of gas = 25°C
Volume of container = ?
Solution:
we will use general gas equation,
PV = nRT
P= Pressure
V = volume
n = number of moles
R = general gas constant = 0.0821 atm.L/ mol.K
T = temperature in kelvin
Now we will convert the temperature.
25+273 = 298 K
Now we will put the values in formula.
2.5 atm × V = 4.0 mol × 0.0821 atm.L/ mol.K × 298 K
V = 97.86 atm.L /2.5 atm
V = 39.14 L
The volume of container is 39.14 L.
The characteristics of two unknown intermolecular attractions, A and B, are compared in the table.
Intermolecular Attractions
A B
Occurs between non-polar diatomic molecules Occurs between polar molecules with either an N, O or F attached to an H atom
Which of the following conclusions about the two attractions is correct? (1 point)
A represents London dispersion forces, and B represents hydrogen bonding.
A represents ion-dipole interactions, and B represents hydrogen bonding.
A represents London dispersion forces, and B represents ion-dipole interactions.
A represents dipole-dipole interactions, and B represents ion-dipole interactions.
Answer:
A represents London dispersion forces, and B represents hydrogen bonding.
Explanation:
The Intermolecular force between two non polar molecules will be weaker London-dispersion forces. The bond between a hydrogen containing molecule with another molecule of an electronegative atom such as O, N etc. is hydrogen bond.
What is intermolecular forces?Intermolecular forces are forces between two molecules that bind them together. The force of attraction is generated by sharing of electrons or by donation of electrons.
Non-polar molecules are those with no charge separation. But when two non-polar molecules comes in contact a temporary dipole will create there and they attract each by the opposite charge ends. This type of force is called London dispersion force.
One molecule with a hydrogen atom is able to form a hydrogen bond with an electronegative atom of another molecule due to the electronegativity difference between hydrogen atom and atoms like N, O, F etc.
Therefore, the intermolecular force A is London-dispersion force and B is hydrogen bonding. Hence, option A is correct.
To find more about intermolecular forces, refer the link below:
https://brainly.com/question/14195217
#SPJ5
Decreasing the volume of a gas increases the pressure of the gas. .
Answer:
False.
Explanation:
If the gas is leaving it cannot have higher pressure.
A bond between a nonmetal and a nonmetal is called a(n)
bond.
A. hydrogen
B. metallic
C. covalent
D. ionic
Answer:
answer: B
Explanation:
becaucse it is B
A bond between a nonmetal and a nonmetal is called a covalent bond. The correct answer is option C.
Covalent bonding occurs when two nonmetal atoms share one or more pairs of electrons in order to achieve a stable electron configuration.
This type of bond is characterized by the sharing of electrons between the atoms, rather than the transfer of electrons as in ionic bonding.
An example of a covalent bond between two nonmetals: The bond between two oxygen atoms in an [tex]\rm O_2[/tex] molecule. In this molecule, the two oxygen atoms share two pairs of electrons to form a stable covalent bond.
Therefore, option C. Covalent bond is a bond between a nonmetal and a nonmetal.
Learn more about covalent bond here:
https://brainly.com/question/19382448
#SPJ6
NEED ANSWER FAST✴️✴️✴️✴️
What do phytoplankton do for the carbon cycle? Choose all that apply.
A. They take in oxygen for photosynthesis.
B. They take in carbon dioxide for photosynthesis.
C. When they die, the carbon left in them can be sequestered (stored) in the ocean bottom.
D. They are food for many animals, including some whales.
Answer:
B is the answer
Explanation:
Which process is represented by this diagram?
Answer:distillation
Explanation:
The process represented by the diagram is chromatography.
What is chromatography?
Chromatography is a separation technique used to separate components present in a mixture.It makes use of two phases the stationary phase and mobile phase .
Stationary phase is a phase in which the mixture components to be separated is loaded. Mobile phase is a phase which is run over the stationary phase so as to enables components of mixtures to separate.
Separation of components is based on the principle that components of mixture which are soluble in mobile phase travel large distances over stationary phase while those which are insoluble or less soluble travel less distances over stationary phase.
For every component which is separated, a Rf value can be calculated which is simply ratio distance traveled by solute divided by distance traveled by solvent front.
Learn more about chromatography ,here:
https://brainly.com/question/11960023
#SPJ2
A cylinder container can hold 2.45L of water. It’s radius is 4.00 cm. What is the volume of it in cubic centimeters?
Answer:
boiiiiiiiiiii
Explanation:
What is the kinetic energy of a 2kg rabbit hopping at a speed of 1.25 m/s
Answer:
What is the kinetic energy of a 2kg rabbit hopping at a speed of 1.25 m/s?1,5625J
Which of the following is not a genetic trait?
Dimples
Hair length
Height
Hair Color
Answer:
I honestly think is hair length
What happens to an atom if it loses an electron?
Answer:
When an atom loses electron(s) it will lose some of its negative charge and so becomes positively charged. A positive ion is formed where an atom has more protons than electrons. In the opposite case when an atom gains electron(s) it becomes negatively charged (more electrons than protons).
Explanation:
Which factors are needed for organisms to live earth
Answer: sunlight, water, air, habitat, and food.
Explanation: we are all living organisms and we all have our five basic necessities for survival; sunlight, water, air, habitat, and food.