express the answer to each of the following calculations in scientific notation with the correct number of significant figures: 45.0 x 270

Answers

Answer 1

Answer: 1.215 × 10^4  i think

Explanation:


Related Questions

What is the mass of 4.39 mol Na?

Answers

Answer:

101 g Na

Explanation:

To convert between moles and grams, you have to use the molar mass of the substance. The molar mass of sodium is 22.99 g/mol. You use this as the unit converter.

[tex]4.39molNa*\frac{22.99gNa}{1molNa} = 100.9261gNa[/tex]

Round the number to the lowest number of significant figures; 101 g Na.

The mass of 4.39 moles of sodium (Na) is 100.97grams.

HOW TO CALCULATE MASS:The mass of a substance can be calculated by multiplying the number of moles in the substance by its molar mass. That is;

Mass = no. of moles × molar mass

According to this question, there are 4.39 moles of Na. The molar mass of Na is 23g/mol.

Mass of Na = 4.39 × 23

Mass of Na = 100.97grams.

Therefore, mass of 4.39 moles of sodium (Na) is 100.97grams.

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Which of the following best describes how Thomson
concluded that electrons are present in all atoms.
a
The charge-to-mass ratio of electrons is always the
same constant, no matter which substances are
used in the cathode ray tube.
b The cathode ray was able to turn a wheel.
The cathode ray always bent toward a negatively
charged plate.
d
The charge-to-mass ratio is unique to each different
element.

Answers

Answer: A

Explanation:

The charge-to-mass ratio of electrons is always the same constant, no matter which substances are used in the cathode ray tube.

Explanation:

Thomson in his model of atom discussed that the atom consists of a negative charge particle termed electron randomly distributed in the positively charged sphere to balance the negative charge.His model of the atom was also known as the Plum pudding model of the atom. In which electrons are embedded in positive soup.He discovered electrons by conducting an experiment with cathode rays in which cathode rays emerging from the cathode were observed to be deflected towards the positively charged plate.He also conducted the same experiment with different metals (for anode and cathode) and gases and found out that the charge to mass ratio of the electron was regardless of the metals or gases used in the experiment.With this, he landed on the conclusion that these particles of cathode rays are the universal component of matter.

So, from this, we can conclude that the charge-to-mass ratio of electrons is always the same constant, no matter which substances are used in the cathode ray tube describes Thomson's conclusion that electrons are present in all atoms.

Learn more about J.J. Thomson's model of atom here:

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How do I do this problem???

Answers

Answer:

i believe it's c

Explanation:

my reason is that if you look at the electrons 2 is the most comm

3.58 x 1023 molecules of propane C8H8 would occupy how much space at STP

Answers

Answer: At STP, a mole of gas takes up 22.4 Liters. The 22.4 Liters/mole quantity can be derived from the Ideal Gas Law, PV = nRT, plugging in STP conditions for P and T, and solving for V/n, which gets 22.4 Liters/mole.

Explanation:

I need help with the 2nd part first gets brainlist

Answers

Answer:

7. 4H₂O

Elements: Hydrogen, Oxygen

Number of molecules: 4

Number of elements: 8 H, 4 O

Number of Atoms: 12

Explanation:

The elements are determined by the their symbol i.e. H = hydrogen.

The number of molecules is determined by the coefficient ( the number in front of everything, in this case 4).

The number of elements is determined by the coefficient and the subscripts. Multiply the coefficient by the subscript after each element. When there is no subscript, it is equal to 1.  4H₂ = 4x2 = 8;  4O = 4x1 = 4.

The number of atoms is all the individual elements added together. 8+4 = 12.

Which of the following elements would be brittle?
Sulfur
Magnesium
Rubidium
Lithium

Answers

Answer:

Sulfur

Explanation:

Sulfur because it is a dull and brittle

Which of the following elements are characterized by having full outermost s and p
orbitals?
F. Period 7
G.
Group 8A
H.
Inner transition elements
J.
Periods 4, 5, and 6

Answers

Answer:

Group 8A

Explanation:

Group 8A elements are characterized by having full outermost s and p orbitals. These elements are also known as the noble gases or inert gases. They occupy the last group on the periodic table.

They are known to have an outer shell configuration of ns² np⁶The configuration reveals that atoms of all the elements have completely filled orbitals in their outer shell sublevels. This accounts for the non-reactivity of elements in this group. Most of the elements in the group have high ionization energy and very low electron affinity values.

Some of the elements in this group are Neon, Argon, Krypton, Xenon, and Radon.


A total of eighteen electrons can be placed into the 3rd energy level.
Explain WHY?

Answers

Answer:

each principal energy level above the second contains, in addition to one s orbital and three p orbitals, a set of five d orbitals, called the d sublevel. The five d orbitals can hold up to 10 electrons. Thus, the third level holds a maximum of 18 electrons: 2 in the s orbital, 6 in the three p orbitals, and 10 in the five d orbitals.

Explanation:

Mark is in charge of making change at his family's garage sale on a hot summer day. He runs low on change and brings out a jar of pennies from the house. He keeps the lid off of the jar. Later in the day, he notices that the pennies are hot. Which statement best explains what happened?\

Answers

Answer:

This question is incomplete

Explanation:

The question is incomplete without the options. However, when a metal (in this case what the pennies are made of) is left in direct contact with the heat from the sun, it conducts this heat and becomes hot. This process is called thermal conduction. The thermal energy is readily accepted by the material in which the pennies are made of thereby increasing the thermal energy of the penny coin  which then makes the pennies hot after being left under the sun.

Use the information below to answer the following questions.

Cyanobacteria, also known as blue-green algae, are a kind of bacteria found in many lakes. These organisms make their own food through photosynthesis. Small animals including mayfly larvae eat the cyanobacteria, and small fish such as yellow perch eat the larvae. The small fish provide food for larger fish, such as walleye.

Describe a model you could use to show the transfer of energy within the lake ecosystem. In your description of your model, make sure you include the position of each organism identified in the paragraph.

Answers

Answer:

sorry don't know wish I could help

2. When one plate is thrust under another plate it will create what landform?
a. Rift valley
b. Mountain range
C. Subduction zone-trench
d. Crater

Answers

Answer:

a

Explanation:

The bright red line from the emission spectrum of hydrogen has a wavelength of 657 nm. What is the energy, in joules, of a single photon of this light? 4.35 x 10–40 J 3.03 x 10–28 J 3.03 x 10–19 J 4.56 x 1014 J

Answers

Answer:

3.03 × 10^-19 J

Explanation:

The energy, E, of a photon of light can be calculated by using the formula:

E = hv

Where; E is energy in Joules,

h is Planck's constant {6.626×10^−34J}

v is frequency of light

For this question, the wavelength (λ) is given, not the frequency (v).

Hence, we use;

v= c/λ

Where v= frequency, c= speed of light (3×10^8m/s), λ= wavelength (657nm)

657nm = 657 × 10^-9m

v = 3×10^8/657 × 10^-9

v = 3/657 × 10^(8--9)

v = 0.00456 × 10^17

v = 4.56 × 10^14

Since frequency (v) = 4.56 × 10^14;

E = hv

E = 6.626×10^−34 × 4.56 × 10^14

E = 30.21 × 10^(-34+14)

E = 30.21 × 10^-20

E = 3.021 × 10^-19

Therefore, the energy of the photon of light is 3.02 × 10^-19 J

How many moles are in 12.6 grams of K2S?

Answers

0.11427369093138474 that’s what I got

A balloon is a sphere with a radius of 5.0 m. The force of air against the walls of the balloon is 45 N. What is the air pressure inside the balloon? Surface area = 12.56 × radius² 1 Pa = 1 N/m² How would I solve this problem? What are the steps or a good way to remeber how to solve?

Answers

Answer:

0.127 N/m² or 0.127 Pa

Explanation:

From the question given above, the following data were obtained:

Radius (r) = 5 m

Force (F) = 40 N

Pressure (P) =.?

Next, we shall determine the Surface area of the sphere (i.e the balloon). This can be obtained as follow:

Surface area = 12.56 × r²

Radius (r) = 5 m

Surface area = 12.56 × 5²

Surface area = 12.56 × 25

Surface area = 314 m²

Finally, we shall determine the pressure as follow:

Force (F) = 40 N

Surface area = 314 m²

Pressure (P) =.?

Pressure = Force /Area

Pressure = 40/314

Pressure = 0.127 N/m² = 0.127 Pa

Therefore, the pressure inside the balloon is 0.127 N/m² or 0.127 Pa.

Which statement best explains why the air pressure is greater at the poles than at the equator

Answers

Answer:

At the equator, the altitude is lower, and also because of the direct heating of sun rays on the surface, the temperature is much higher than at the poles. This makes the air near the surface hot and lighter and hence it rises up which results in lower air pressure.

Explanation:

Plz give me brainliest .-.

During evaporation, what causes certain liquid molecules to become vapor molecules? A. Decreased fluidity A. Increased viscosity A. Decreased kinetic energy A. Increased kinetic energy.

Answers

Answer:

The answer is A. Decreased Fluidity

Explanation:

Taking the test on preformance matters

In evaporation, particles of liquids take energy in the form of sunlight from the surrounding and then convert into vapor phase. Increased kinetic energy causes certain liquid molecules to become vapor molecules.

What is evaporation?

Evaporation is a physical process in which the water in liquid state converts to gaseous state at the temperature below its boiling point. Evaporation happens before the boiling process.

Evaporation causes cooling effect in the surrounding. During summer when water is kept in earthen pot water cools, this is because of the evaporation process.

Evaporation is affected by temperature. As the temperature increases, kinetic energy of liquid molecules also increases and hence the rate of evaporation increases.

Therefore, increased kinetic energy causes certain liquid molecules to become vapor molecules.

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What is the atomic number of an atom?
O the number of neutrons
O the number of electrons and neutrons
O the number of protons
the number protons and neutrons

Answers

The answer is the number of protons. I hope this helps
An atom is classified by how many protons it has.

Changes in the number of neutrons will change the individual isotope of that element that the atom is, but the atomic number is always equal to the number of protons.

Also, protons + neutrons = mass number, not atomic number!

Identify the property of the matter described below.

Alcohol floats on top of the water.
A-pH
B-conductivity
C-density
D-luster

Answers

Answer: C.

Explanation: Alcohol floats on oil and water sinks in oil. Water, alcohol, and oil layer well because of their densities, but also because the oil layer does not dissolve in either liquid. The oil keeps the water and alcohol separated so that they do not dissolve in one another. ... Water sinks because it is more dense than oil.

stages of mitosis in order

Answers

Answer:

nucleus formed

prophase

metaphase

anaphase

telophase and cytokinesis

Which types of matter are made of atoms

a. Mixtures
b. Elements
C. Compounds
D. All of the above

Answers

Answer:

D all above yes I think it's all above

Answer:  D

Explanation: All of the above.

Plz mark brainliest:)

what is the median number of 69,64,63,66?

Answers

the answer is 67.5. hope this helps
65

First put them in order from least to greatest. Then remove outer numbers. You are then left with 64 and 66. The number in the middle of 64 and 66 is 65.

What explains the structure of metals and delocalized electrons?

A. the unit cell model

B. the geometric shape model

C. the covalent bond model

D. the electron sea model

Answers

D the electron sea model

which of the following elements would decrease in size when it became an ion

Answers

Answer:

nickel, cobalt would decrease in size when it became an iron

What is the mass of an object with a density of 5.7 g/cm^3 and a volume of 48
cm^3? *

Answers

Answer:

273.6 g

Explanation:

mass =(density)(volume)

mass=(5.7g/cm^3 )(48 cm^3)

cancel out your cm^3 and your are left with grams

multiply (5.7g)(48)=273.6 g

The mass of an object with a density of 5.7 g/cm³ and a volume of 48 cm³ is 273.6 grams.

What is density?

Density is defined as the degree to which a material is packed together.

It is also defined as a mass per unit volume of the substance.

Its SI unit is kilogram per cubic meter or  gram per meter.

Density can be expressed as

Density = mass / volume

Mass =  density x volume

As given, Density = 5.7 g/cm³

                Volume = 48 cm³

So, Mass =  5.7 g/cm³ x  48 cm³

               =  273.6 grams

Thus, the mass of an object with a density of 5.7 g/cm³ and a volume of 48 cm³ is 273.6 grams.

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1 pc
Calculate the volume of a an object that has a height of 14.3cm, length or
25.2cm, width of 6.7cm. *
46.2cm
2414.412 cm
0.085 cm
53.785 cm

Answers

Answer:0.085

Explanation:

When many earthquakes are studied, there is another common pattern that emerges: a "Shadow Zone". This is an area, for any earthquake, on the Earth where direct S-waves don't arrive at all and P waves are refracted. What do you think causes these P waves to be refracted? *

Answers

Answer:

Sudden decrease in the velocity at the boundary.

Explanation:

The shadow zone is the zone of the earth from angular distances of 104° to 140° from a known earthquake that does not directly receive any P waves. Now, this shadow zone occurs as a result of S waves getting stopped completely by the liquid core and the P waves being refracted by the liquid core.

From earlier seismic discoveries, this boundary which is the shadow zone that does not directly receive any P-waves was found to be due to the fact that the P-waves were refracted inwards as a result of the sudden decrease in velocity at the boundary.

What is force and motion

Answers

force is a strength or energy as an attribute or physical action or movement, motion is the action or process of moving or being moved

Answer:

In physics, a force is any interaction that, when unopposed, will change the motion of an object. A force can cause an object with mass to change its velocity (which includes beginning moving from a state of rest), i.e., to accelerate. Force can also be described intuitively as a push or a pull.

= google

lol

Which of the following is the correct model of C7H16?
A.
B.
C.
D.

Answers

Answer:

D

Explanation:

Option D gives the correct model of C7H16. From the option, one will discover that the model has 7 carbons in the backbone. If you count the attached hydrogen, you will discover that the hydrogen is 16 in total.

This model or skeletal structure of this element represents heptane. Heptane or n-heptane is known to be a straight-chain compound and an alkane. It's chemical formula can also be written as: H₃C(CH₂)₅CH₃ or C₇H₁₆.

This compound is known to be one of the main components of gasoline. It is known to be a volatile organic compound and a clear and colorless liquids with a petroleum-like odor.

Answer: D

Explanation: Just took the test

25 cm of liquid 'A' and 20 cm of liquid
'B' are mixed at 25°C and the volume of
solution was measured to be 44.8 cm3
then correct reaction is
(A) A Hmix = 0, solution shows
ideal

Answers

Answer:

The correct option is;

(B) [tex]\Delta H_{mix} < 0[/tex], solution shows negative deviation

Explanation:

The given parameters are;

The available volume of liquid A = 25 cm³

The available volume of liquid B = 20 cm³

The volume of the solution (mixture) = 44.8 cm³

Therefore, we have;

[tex]\Delta _{mix} V < 0[/tex]

Which is one of the prerequisite for the formation of negative deviation

When a non-ideal solution shows negative deviation according to Raoult's Law, we have;

[tex]\Delta _{mix} H < 0[/tex], we have more heat released due to new molecular interactions.

why can dogs not eat chocolate

Answers

it’s poisonous to them :(((
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