What is the total number of electrons in an atom of an element with an atomic number of 18 and a mass number
of 402
a. 58
c. 22
b. 18
d. 40

Answers

Answer 1

Answer:

18

Explanation:


Related Questions

Help please and thank you so much

Answers

I think it’s A I’m not positive about this question

Answer:

A

Explanation:

there cnt be an increase photosynthesis.

surely when its cold,leaves dropped.

Magnesium is a metal that is commonly used in products that need to be lightweight. Suppose a 2.00-kg piece of magnesium has 8160 J of energy added to it. Its temperature increases 4k. What is the specific heat of magnesium. Show your work

Answers

Answer:

The specific heat of magnesium is 1.02 J/g.K

Explanation:

To calculate the energy involved in the heating of the metal (magnesium), we use the following expression:

energy = mass x Cp x ΔT

We have the following data:

mass = 2.00 kg x 1000 g/1.00 kg = 2000 g

energy = 8160 J

ΔT = 4 K

Thus, we can calculate the specific heat of magnesium (Cp) in J/g.K as follows:

⇒ Cp = energy/(mass x ΔT) = 8160 J/(2000 g x 4K) = 1.02 J/g.K

How many chlorine aHow many chlorine atoms are there in 4 molecules of CH2Cl2?

Answers

If there is 4 of CH2CI2, then there is 8 of CI. There is already 2 in each one and there is 4 sets so 2x4=8

....Which is the best classification for West Nile virus?
food-borne illness
irradiated disease
antibiotic resistant bacteria
emerging infectious disease

Answers

Answer:

D.

Explanation:

Emerging infectious disease

Answer:

d

Explanation:

emerging infectious disease

Calculate the number of molecules in 895 g of H2O.

Answers

Answer:

The number of molecules in 895 g of H₂O is 4.49*10²⁵.

Explanation:

Avogadro's Number or Avogadro's Constant is called the number of particles that make up a substance (usually atoms or molecules) and that can be found in the amount of one mole of said substance. Its value is 6.023*10²³ particles per mole. Avogadro's number represents a quantity without an associated physical dimension, so it is considered a pure number that allows describing a physical characteristic without an explicit dimension or unit of expression. Avogadro's number applies to any substance.

In this case, the molar mass of compound H₂O is 18 g / mol. So if 18 grams of H₂O are present in 1 mole, 895 grams will be present in how many moles of H₂O?

[tex]moles of H_{2}O=\frac{895 grams*1 mole }{18 grams}[/tex]

moles of H₂O= 74.58

Then the following rule of three can be applied: if 1 mole of the compound contains 6.023 * 10²³ molecules by definition of Avogadro's number, 74.58 moles of the compound how many molecules will it contain?

[tex]amount of molecules=\frac{74.58 moles*6.023*10^{23}molecules }{1 mole}[/tex]

amount of molecules=4.49*10²⁵

The number of molecules in 895 g of H₂O is 4.49*10²⁵.

______cells have long projections that help carry electrical messages to other cells.
O striated
O nerve
O smooth
O muscle

Answers

Answer: Nerve cells!

its the nerve cell which carry electrical message to others cell.

What is the density of butane (C4H10) at STP?

Help please

Answers

Answer:

his means 1 mole of butane has a volume of 22.4dm3 at STP. 1 mole of butane has the same mass in grams as its relative molecular mass.

Exactly What they said ^

Which of the following are examples of chemical energy being released or stored? (2 points)

A boy eating an orange to survive
A car burning gasoline to move
The sun heating a rock

Select two answers

Answers

A boy eating a orange to survive because it’s going in his stomach and the sun heating a rock because Heat from the sun causes rock to crack or buckle from pressure caused by its atoms' increasing speed.

HELP ME PLS HURRY I NEED THIS ANSWER ASAP !!!!

Answers

Answer:

0.1 im pretty sure

because

All those squares equal to 1

So if we use some good ole division

We get 0.1

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!!

hey guys can u help me ASAP its on science

Answers

Answer:

The answer to your question is A - electrons

Explanation:

To be honest it's pretty obvious, none of the other things could possibly come with valence behind it so electrons is the only logical answer.

Answer:

A. electrons

Explanation:

The valence electrons on the valence shell which is the last layer of electrons are the same for atoms in the same column.

How many atoms are in the chemical formula shown? HCIO3

Answers

Answer:

5

Explanation:

chemical formulas show what atoms are in a molecule.  In this case there is 1 hydrogen (H), 1 chlorine (Cl), and 3 oxygens (O).  The 3 behind the oxygen is a subscript and tells us that there are 3 oxygen atoms.

Another example is H2O which as 3 atoms. 2 hydrogens (H) and 1 oxygen (O).  This formula has a subscript 2 behind the hydrogen showing that there are 2 hydrogens.

Help me ASAP Pls!!!!

Answers

Answer:

the answer is the second option

Explanation:

hope you have a great day though!

How much energy is required to boil 65 grams of 100°C water
And then heat the steam to 150°C?

Answers

Answer:

13598 J

Explanation:

Q = m × c × ∆T

Where;

Q = amount of energy (J)

m = mass (grams)

c = specific heat capacity

∆T = change in temperature

m = 65g, specific heat capacity of water = 4.184J/g°C, initial temperature= 100°C, final temperature = 150°C

Q = 65 × 4.184 × (150 - 100)

Q = 271.96 × 50

Q = 13598 J

Hence, 13598 J of energy is required to boil 65 grams of 100°C water and then heat the steam to 150°C.

Determine the molar mass of Ze(NO3)2. (Ze=55.85 N=14.01 O=16.00) *
Help

Answers

Answer:

179.87 g/mol

Explanation:

First you need to determine the number of each elements in the molecule.  This information comes from the molecular formula.  

Ze(NO3)2 tells us that there is 1 Ze atom and 2 NO3 anions per molecule.  each NO3 anion will have 1 nitrogen and 3 oxygens.  Due to that, one molecule of Ze(NO3)2 will have 1 atom of Ze, 2 atoms of nitrogen (N), and 6 atoms of oxygen (O).

Next you need to add all of the individual atom's molar masses to get the over all molar masses.  The molar masses of each element is in the question but it can also be found on the periodic table.

molar mass of Ze(NO3)2 = 55.85g/mol + (14.01g/mol*2) + (16.00g/mol*6)

molar mass of Ze(NO3)2 = 179.87 g/mol

I hope this helps.

1. Which of the following equations is balanced?
a. Al + Br2- 2A1Br3
b. 2Al + 2Br2 → 3AlBr3
c. 2Al + 3Br2 → 2AlBr3
d. Al + Br2 → AlBr3

BRAINLIEST BRAINLIEST
please answer I’m trying to work with 0 hours of sleep :)

Answers

The answer would be A

For the problem: Mg (s) + O₂ (g) ➞ MgO (g) if 4.3 g of magnesium reacts with 83 g of oxygen (O₂), which is the limiting reagent? *
4 points
magnesium
oxygen
magnesium oxide
dimagnesium dioxide

Answers

Explanation:

hope this can help youuu

The following reaction shows calcium chloride reacting with silver nitrate.
CaCl2 + 2AgNO3 → 2AgCl + Ca(NO3)2
How many grams of Ca(NO3)2 are produced from 2,000.0 grams of AgNO3?
(Molar mass of Ca = 40.1 g/mol, Cl = 35.5 g/mol, O = 16.0 g/mol, Ag = 107.9 g/mol, N = 14.0 g/mol)
(Show your calculations for full credit. Correct answers will only receive partial credit.)

Answers

Grams of Ca(NO₃)₂ produced : 0.985 g

Further explanation

A 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

CaCl₂ + 2AgNO₃ → 2AgCl + Ca(NO₃)₂

MW AgNO₃ : 107.9+14+3.16=169.9

mol AgNO₃ :

[tex]\tt \dfrac{2}{169.9}=0.012[/tex]

mol ratio Ca(NO₃)₂ : AgNO₃ = 1 : 2, so mol Ca(NO₃)₂ :

[tex]\tt \dfrac{1}{2}\times 0.012=0.006[/tex]

MW Ca(NO₃)₂ : 40.1+2.14+6.16=164.1 g/mol

mass Ca(NO₃)₂ :

[tex]\tt 0.006\times 164.1=0.985[/tex]

plzzz helppppppp!!!!!!!!!!!♥️♥️i only have 2 mins to complete this!!!!

Count the number of elements in the following molecule: 3 C2(H6K5)2​

Answers

Answer:

3 elements

Explanation:

Carbon, helium, and potassium

Show your work with good use of units, rounding, and significant figures. [Hint: it is good practice to show the value of your answer before you round off to the final answer with the correct significant figures!]

(8 points) How much heat is required to convert 10.00 g of ice at –20.00°C to water at 25°C. The specific heat of ice is 2.09J/g°C; the specific heat of water is 4.182 J/g°C; the heat of fusion is 333.0 J/g.

Group of answer choices

Answers

Heat required : 4.8 kJ

Further explanation

The heat to change the phase can be formulated :

Q = mLf (melting/freezing)

Q = mLv (vaporization/condensation)

Lf=latent heat of fusion

Lv=latent heat of vaporization

The heat needed to raise the temperature

Q = m . c . Δt

1. heat to raise temperature from -20 °C to 0 °C

[tex]\tt Q=10\times 2.09\times (0-(-20)=418~J[/tex]

2. phase change(ice to water)

[tex]\tt Q=10\times 333=3330~J[/tex]

3. heat to raise temperature from 0 °C to 25 °C

[tex]\tt Q=10\times 4.18\times (25-0)=1045~J[/tex]

[tex]\tt Q~tot=418+3330+1045=4793~J\rightarrow rounding~and~2~sig~figs=4.8~kJ[/tex]

Arrange the events of succession after a volcano erupted in their proper order

Answers

Answer:

pioneer species, soil formation, plant growth

Explanation:

The events of succession after a volcano erupted in the proper order include pioneer species being visible. The pioneer species such as algae and Moss are usually found on rocks and dead matter.

After sometime the soil starts to form through weathering activities which then gives rise to and supports the growing of plant species.

true or false, the melting point of gold is more than 1,000°c

Answers

Answer:

Explanation:

true it is 1064 c

Answer:

true

Explanation:

it's 1064º C

Part C
In the Options window of the simulation, select Pie to show the pie chart. In the window labeled Start with how many, use the up arrows to add 40 particles of A and 40 particles of BC. Then press the Begin experiment button. Wait a few seconds for the reaction to come to equilibrium, and then click pause near the bottom of the screen.

Study the graph on the left. The green line shows total average energy. The blue line shows the amount of potential energy possessed by the reactants and the products. Recall that substances most readily take the form in which they have the least potential energy. The amount of potential energy can be adjusted, affecting the outcome of the reaction. Recall that in the initial experiment for synthesizing ammonia, only about 20% of the reactants were converted to the products.

Click the Play arrow to resume the simulation. Then adjust the potential energy curve so the proportion of reactants to products is roughly the same as the proportion in the initial experiment. Adjust the center slider up or down so there’s a bump in the middle of the energy curve. The bump represents the energy the particles must have to react. Take a screenshot of the energy curve, and use the Insert Image button to paste it in the answer space.

Answers

Answer:

Explanation:

I'm not going to lie, I think I did this completely wrong. But you can use this. I was completely lost on this assignment.

Answer:

I believe this is the answer

Explanation:

An unknown metal with a mass of 585.6 grams, changes temperature from 46.5°C to 84.5°C when it absorbs 795J of energy. Find specific heat of the unknown metal.

Answers

Answer: So the answer would be um I dont

know the answer right now but message me later on and I will help

Explanation: The equation that relates heat  (q) to specific heat (c_p) , mass (m), and temperature change  (Delta{T}) is shown below.

q=c_p times m times Delta{T}  The heat that is either absorbed or released is measured in joules. The mass is measured in grams. The change in temperature is given by Delta{T}= T_f - T_i , where  T_f is the final temperature and  T_i is the initial temperature. Step 1: List the known quantities and plan the problem .

Known

heat = q = 134 J

mass =  m = 15.0 g

Delta{text{T}} = 62.7^circ text{C} - 24.0^circ text{C} = 38.7^circ text{C}

Unknown

c_p text{of cadmium}= ? text{J}/ text{g}^circ text{C}

The specific heat equation can be rearranged to solve for the specific heat.

Step 2: Solve .

c_p=frac{q}{m times Delta{T}}=frac{134 text{ J}}{15.0 text{ g} times 38.7^circ text{C}}=0.231 text{ J/g}^circ text{C}

Step 3: Think about your result .

The specific heat of cadmium, a metal, is fairly close to the specific heats of other metals. The result has three significant figures.

Since most specific heats are known, they can be used to determine the final temperature attained by a substance when it is either heated or cooled. Suppose that a 60.0 g sample of water at 23.52°C was cooled by the removal of 813 J of heat. The change in temperature can be calculated using the specific heat equation.

Delta{T}=frac{q}{c_p times m}=frac{813 text{ J}}{4.18 text{ J/g}^circ text{C} times 60.0 text{ g}}=3.24^circ text{C}

Since the water was being cooled, the temperature decreases. The final temperature is:

T_f=23.52^circ text{C} - 3.24^circ text{C}=20.28^circ text{C}

Determined which equation is balanced or unbalanced.

Answers

Answer:

1. balanced

2.unbalanced

3.unbalabced

4.balanced

Agree or disagree
The sun and stars move around earth everyday​

Answers

Agree definitely :P poop dance

A 100kg sumo wrestler named Bob is doing his daily run. He runs at a velocity of 8m/s. After the run Bob stops for a rest, and sits at the river.
What is Bob's momentum will resting at the river?
Question 10 options:
800 kgm/s
800 kgm/s^s
0 kgm/s
12.5 kgm/s^2

Answers

Answer:

0 kgm/s

Explanation:

The momentum of Bob while resting at the river is 0 kgm/s.

This is because the momentum of any object at rest is 0.

 Momentum is the quantity of motion a body contains. It is mathematically expressed as;

  Momentum  = m x v

m is the mass

v is the velocity

 So at rest, the velocity of a body is 0m/s and therefore, the momentum is O

2. The heat energy fequired to change a
unit mass of a solid into a liquid at
constant temperature is called
(1) heat of vaporization
(2) heat of formation
(3) heat of solution
(4) heat of fusion

Answers

Heat of solution (I believe)

Which of the following characteristics is not necessary an organism to be considered living?

A. All living things grow and develop.
B. All living things move.
C. All living things reproduce.
D. All living things have DNA.

Answers

B. All living things move
B is the answer bc all living don’t have to move to considered living

Which reactant will be used up first if 78.1g of o2 is reacted with 62.4g of c4h10?
A. c4h10
B. o2
C. co2
D. h2o

Answers

Answer:

Reagent O₂ will be consumed first.

Explanation:

The balanced reaction between O₂ and C₄H₁₀ is:

2 C₄H₁₀ + 13 O₂ → 8 CO₂ + 10 H₂O

Then, by reaction stoichiometry, the following amounts of reactants and products participate in the reaction:

C₄H₁₀: 2 molesO₂: 13 moles CO₂: 8 moles H₂O: 10 moles

Being:

C: 12 g/moleH: 1 g/moleO: 16 g/mole

The molar mass of the compounds that participate in the reaction is:

C₄H₁₀: 4*12 g/mole + 10*1 g/mole= 58 g/moleO₂: 2*16 g/mole= 32 g/moleCO₂: 12 g/mole + 2*16 g/mole= 44 g/moleH₂O: 2*1 g/mole + 16 g/mole= 18 g/mole

Then, by reaction stoichiometry, the following mass quantities of reactants and products participate in the reaction:

C₄H₁₀: 2 moles* 58 g/mole= 116 gO₂: 13 moles* 32 g/mole= 416 gCO₂: 8 moles* 44 g/mole= 352 gH₂O: 10 moles* 18 g/mole= 180 g

If 78.1 g of O₂ react, it is possible to apply the following rule of three: if by stoichiometry 416 g of O₂ react with 116 g of C₄H₁₀, 62.4 g of C₄H₁₀ with how much mass of O₂ do they react?

[tex]mass of O_{2} =\frac{416grams of O_{2}*62.4 grams ofC_{4}H_{10} }{116 grams of C_{4}H_{10}}[/tex]

mass of O₂= 223.78 grams

But 21.78 grams of O₂ are not available, 78.1 grams are available. Since you have less mass than you need to react with 62.4 g of C₄H₁₀, reagent O₂ will be consumed first.

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