an atom has 19 protons and 20 neutrons. what is the atomic number with steps​

Answers

Answer 1

Answer:

39

Explanation:

add em up


Related Questions

Scientists use carbon dating to determine the age of fossils. 14C is a rare isotope of carbon that has a half life of 5730 years and decays into 14N. By measuring the amount of 14C remaining in a fossil, scientists can estimate when the organism died out to about 60,000 years. The atomic number of C is 6, and of N is 7. 14C and 14N have the same: Group of answer choices

Answers

Answer:

The correct answer is - mass number.

Explanation:

The atomic number the number of electrons or protons present in a neutral atom.

Atomic number = Number of electrons = Number of protons

Whereas, the mass number the sum of the number of protons and the number of neutrons present in an atom.

Mass number = Number of protons + Number of neutrons

For C-14 and N-14:

C-14 isotope:

Atomic number = number of proton = number of electron = 6.

Mass number = 14

Number of neutrons = 14 - 6 = 8

In N-14 isotope:

Atomic number = number of proton = number of electron = 7

Mass number = 14

Number of neutrons = 14 - 7 = 7

Thus, these two isobars have same mass number.

Which of the following answer describes 1-pentyne?

O structure should have 5 carbon with double bond beginning on the 1st carbon atom
O structure should have 6 carbon with triple bond beginning on the 1st carbon atom
O structure should have 6 carbon with double bond beginning on the 1st carbon atom
O structure should have 5 carbon with triple bond beginning on the 1st carbon atom

Answers

Answer:

The answer is that the structure should have 5 carbon with triple bond beginning on the 1st carbon atom.

Explanation:

The structure will have 5 carbons since the -pent prefix means 5 carbons.

The structure has a triple bond because the -yne suffix means that the structure is an alkyne. An alkyne is a hydrocarbon with triple covalent bonds.

Also, the position of the triple bond is known because the nomenclature of the alkyne states that the triple bond is on the 1st carbon.  

What is the percent yield of a reaction that has a theoretical yield of 50.0 grams of product but after an experiment you only collect 40 grams of product?

Answers

May solution ba o wala tanong kolang

The percent yield of a reaction is 80%

The theoretical yield of the product is 50.0 g

The actual yield of the product is 40 g

We need to calculate the percent yield of the reaction.

What is the percent yield?

The percent yield describes the ratio of the actual yield and the theoretical yield expressed as a percentage value.

The formula of percent yield is shown as

[tex]Percent\ yield =\ \frac{actual\ yield} {theoretical\ yield} \times 100[/tex]

Now, putting the given values as

[tex]Percent\ yield =\ \frac{40} {50} \times 100[/tex]

Percent yield = 80 %

Therefore, the percent yield of a reaction is 80%

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Which rock among the given rocks is most likely to erode away the fastest?
Please give 1 answer.
A.
Marble
B.
Granite
c
.
Sandstone
D.
Basalt

Answers

Answer:

The answer is B............

Answer:

b. Granite

Explanation:

Soft rock like chalk will erode more quickly than hard rocks like granite. Vegetation can slow the impact of erosion. Plant roots adhere to soil and rock particles, preventing their transport during rainfall or wind events.

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increases/decreases from left to right across a period.WHY do we observe this periodic trend?

Answers

The atomic radius of atoms generally decreases from left to right across a period. There are some small exceptions, such as the oxygen radius being slightly greater than the nitrogen radius. ... Since the force of attraction between nuclei and electrons increases, the size of the atoms decreases.

Answer:

don't no answer

Explanation:

d don't no answer

If 0.500 moles of silver nitrate were consumed, how many moles of calcium nitrate would be produced?(make sure to balance the chemical equation first)
AgNO3 + CaCl2 → Ca(NO3)2 + AgCl

Answers

Answer:

Explanation:

AgNO3 + CaCl2 ⇒ Ca(NO3)2 +AgCl

2AgNO3 + CaCl2 ⇒ Ca(NO3)2 + 2AgCl

what is the volume of 72g of copper has a density of 9/cm 3

Answers

volume = mass /density
v=72/9=8
so the density is 8g/ml

Answer:

8cm³

Explanation:

density = mass/volume

or volume = mass/density

= 72/9

= 8 cm³

A baseball player hits a ball. Which is the best description of the energy of the ball as it flies over the pitcher's head?
O chemical
O kinetic
O nuclear
O thermal

Answers

The correct answer is B. Kinetic

The simple activities like walking, jumping, throwing and falling usually involves kinetic energy. Here the energy of ball when a baseball player hits a ball is kinetic energy. The correct option is B.

What is kinetic energy?

The kinetic energy of an object is defined as the measure of the work that an object does by virtue of its motion. When work is done on an object, energy is transferred and the object moves with a constant speed. This energy transferred is kinetic energy.

It is possible to transfer kinetic energy between objects and can be transformed into other form of energy. The SI unit of kinetic energy is Joule and it is proportional to the square of velocity and mass of the object.

Here the moving ball has kinetic energy due to its stae of motion.

Thus the correct option is B.

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explain observation made when anhydrous calcium chloride and anhydrous copper (ii) sulphate are separately exposed to the atmosphere for about two days​

Answers

Answer:

Anhydrous calcium chloride  dissolves and becomes liquid

Anhydrous copper (ii) sulphate will produce crystal particles

Explanation:

Anhydrous calcium chloride is deliquescent and hence when it is exposed to air, it absorbs water from air. After absorbing water, it dissolves and after some time a pool of clear liquid appears.

Anhydrous copper (ii) sulphate will form crystal structures  and the following reaction will takes place

CuSO4 + 5 H20 --> CuSO4.5H2O

Unit Test Review
Active
1
2
3
According to the kinetic-molecular theory, what happens to a liquid when it is transferred from one container to
another?
O The volume and the shape stay the same.
O The volume increases to fill the new container, but the shape stays the same.
O The volume stays the same, but the shape changes to fit the new container
O The volume and the shape change to fill the new container

Answers

Answer:

the volume stays the same, but the shape changes to fit the new container

Explanation:

because the same amount/volume of liquid is being placed in a new container, the new container has a different shape to the old, thus changing the liquids shape but not volume.

Which statement about Niels Bohr’s atomic model is true?

Answers

Answer:

Each orbit has a specific energy level.

Would you mind marking it the brainliest:).

A female rabbit had 4 babies. For phenotypes: two of the babies were black and two of the babies were white. In rabbits, the allele for black fur (B) is dominant to the allele for white fur (b). Identify the genotypes of the mom and dad rabbit and complete the Punnett square to show how the 4 babies got their fur color.

Answers

Answer:put the rabbits mixed

Explanation:

explain what you understand by valency, give examples​

Answers

Answer:

Valency is defined as the number of hydrogen atoms which combine directly or indirectly with one atom of an element.

Example:

One atom of nitrogen combines with three atoms of hydrogen to form ammonia gas. So, the valency of nitrogen is 3.

Phosphorous is prepared according to the following equation: Ca3(PO4)2 + 3SiO2 + 5C = 3CaSiO3 +5CO + 2P
What mass of phosphate rock (Ca3(PO4)2) is necessary to produce 9700. kg of phosphorous?

Answers

Answer:

48546.7kg or 48546745g

Explanation:

so from this u can work out the amount of moles in phosphorous by doing mass / mr you have to convert the mass in kg to g so you times it by 1000. then divide it by 31 which is the mr of phosphorous. then u can use the molar ratio which is 2:1 . Then use the equation mass= moles*mr

so 97000*1000/31=312903moles

2:1

so 312903/2=156451 moles of ca3(PO4)2

so mass= moles*mr

156451*310.3=48494g

hope this helps u to understand(*°▽°*)

Adam is doing a science project. He wants to find out how the height of the Sun affects the length of shadows. He will measure the shadow of his house at different times. He will see when the shadow is the longest.

Which is a scientific prediction Adam could make about his project?
A.
The Sun is highest at noon.
B.
The shadow will be longest in the morning.
C.
My shadow is shorter than the shadow of my house.
D.
I found out that the shadow is shortest at noon.

Answers

Answer:

d I think there's two answer

Explanation:

or c

Match each element or compound with the appropriate symbol or molecular formula. Carbon dioxide CO2 carbon o oxygen Н H water с hydrogen H2O

Answers

Answer:

Carbon dioxide ---> CO₂

Water ----> H₂O

Carbon ---> C

Oxygen ----> O₂

Hydrogen ----> H₂

Explanation:

The molecular formula of an element or compound is a formula which represents the composition of a molecule of that element or compound. It consists of the formula representing the atoms present as well as the number of atoms of each element innthe compound written as subscript innthe formula of the element or compound.

The molecular formula of the given elements and compounds are given below:

Carbon dioxide ---> CO₂

Water ----> H₂O

Carbon ---> C

Oxygen ----> O₂

Hydrogen ----> H₂

The molecular formula of carbon dioxide shows that in a molecule of carbon dioxide, there are two atoms of oxygen and one atom of carbon present in a molecule of carbon dioxide.

The molecular formula of water shows that are two atoms of hydrogen and one atom of oxygen present in a molecule of water.

The molecular formula of carbon shows that there are one carbon atoms in a molecule of carbon.

The molecular formula of oxygen shows that there are two oxygen atoms in a molecule of oxygen gas.

The molecular formula of hydrogen shows that there are two molecules of hydrogen in a molecule of hydrogen gas.

ASAP PLS
Identify the correct formula for each of the following compounds.

Carbon tetrabromide

4CBr

CBr4

C4Br

Chlorine monofluoride

ClF

FCl

Cl1F1

Answers

Answer:

1.CBr4

2.CIF

Explanation:

Covalent compound are formed by sharing of electron and ionic compound formed by complete transfer of electron. The chemical formula for Carbon tetrabromide is CBr₄ and for Chlorine monofluoride is ClF.

What is chemical Compound?

Chemical Compound is a combination of molecule, Molecule forms by combination of element and element forms by combination of atoms in fixed proportion.

Ionic compounds are more stronger than covalent compound. Ionic compounds have higher melting and boiling point than covalent compounds.

The chemical formula for Carbon tetrabromide is CBr₄, tetra means four. The chemical formula for Chlorine monofluoride is ClF, mono means one.

Therefore, the chemical formula for Carbon tetrabromide is CBr₄ and for  Chlorine monofluoride is ClF.

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Which of the following correctly describes the role of the mouth in the digestive system?

The mouth acts like a muscular bag by churning the food and producing enzymes that aid in chemical digestion.


The mouth produces all of the enzymes needed for digestion and these enzymes are swallowed, which moves them through the digestive tract.


The mouth begins the process of digestion by mechanically breaking food into smaller pieces.


The mouth performs the peristalsis that pushes food through the rest of the digestive system.

Answers

Answer:

The mouth begins the process of digestion by mechanically breaking food into smaller pieces.

Explanation:

Digestion is a crucial process that involves the break down of complex food molecules into simpler ones that are assimilable by the body. The process of digestion in humans, for example, is said to begin in the MOUTH where the food enters through.

The mouth via the use of teeth helps the initially break down the food particles using mechanical/physical method. This further helps the break down of the food into tiny particles before they are acted on enzymatically.

(b) When water reacts with potassium metal the hydrogen produced ignites explosively
on the surface of water.


(ii) Write an equation to show how this ignition occurs.

Answers

2K(s) + 2H2O(l) → 2KOH(aq) + H2(g)

A student creates a model of a closed ecosystem by filling a glass tank half
full with water, then adding 10 snails and two small aquatic plants. The next
day, all the snails are dead. What is the most likely cause of their death?
A. The rates of cellular respiration and photosynthesis in the tank
were both too high.
B. The rates of cellular respiration and photosynthesis in the tank
were both too low.
O C. The rate of cellular respiration in the tank was much higher than
the rate of photosynthesis.
D. The rate of photosynthesis in the tank was much higher than the
rate of cellular respiration.
SUBMIT
e
PREVIOUS

Answers

Answer:

C. The rate of cellular respiration in the tank was much higher than

the rate of photosynthesis

Explanation:

In nature, cellular respiration and photosynthesis are opposite metabolic reactions. Cellular respiration, which is the process of releasing energy, requires oxygen while photosynthesis, which is the process of manufacturing foods by green plants, releases oxygen into the atmosphere. The two equations are as follows:

Photosynthesis:

6CO2 + 6H2O → C6H1206 + 6O2 (oxygen released)

Respiration:

C6H1206 + 6O2 (oxygen used) → 6CO2 + 6H2O

According to this question, 10 snails and two small aquatic plants were added to a closed glass tank half full with water. It was observed that all the snails died. This is most likely due to the fact that the rate of cellular respiration in the tank was much higher than the rate of photosynthesis.

In other words, the usage of oxygen via cellular respiration was much higher than the release of oxygen via photosynthesis.

Answer:

1. Snails carry out respiration only

2. Aquatic plants carry out both respiration and photosynthesis Although the aquatic plants can absorb carbon dioxide and release oxygen through photosynthesis, the amount of snail is much more than that of the aquatic plants.

During night time,the absence of light prevent the plants from carrying out photosynthesis. No oxygen is released at this time. There is a net release of carbon dioxide in the closed system and hence the snail died of suffocation.

A gas initially has a volume of 300. mL at a pressure of 1.0 atm, what will the
new volume be if the pressure is doubled? (assume constant temperature)

Answers

The new pressure will be
1000 L
, rounded to one significant figure.
Explanation:
Boyle's law states that when a gas is held at a constant temperature and mass in a closed container, the volume and pressure vary inversely. The equation to use is
P
1
V
1
=
P
2
V
2
.
Given
V
1
=
200
mL
×
1
L
1000
mL
=
0.2 L

P
1
=
700 mmHg

V
2
=
100
mL
×
1
L
1000
mL
=
0.1 L

Unknown
P
2

Equation
P
1
V
1
=
P
2
V
2

Solution
Rearrange the equation to isolate
P
2
and solve.
P
2
=
P
1
V
1
V
2

P
2
=
(
700
mmHg
×
0.2
L
)
0.1
L
=
1400 L
, which must be rounded to
1000 L
because all of the measurements have only one significant figure.

If 11 kJ of heat is transferred to 2300 g of soil at 21°C, what would the new temperature of the soil be?

Answers

Answer:

26.98°C

Explanation:

Applying,

Q = cm(t₂-t₁)................ Equation 1

Where Q = Heat transferred to the soil, c = specific heat capacity of dry soil, m = mass of the soil, t₂ = final temperature, t₁ = initial temperature.

From the question,

Given: Q = 11 kJ = 11000 J, m = 2300 g = 2.3 kg, t₁ = 21°C

Constant: c = 800 J/kg.°C

Substitute these values into equation 1

11000 = 800×2.3(t₂-21)

Solving for t₂

t₂-21 = 11000/(800×2.3)

t₂-21 = 11000/1840

t₂-21 = 5.98

t₂ = 5.98+21

t₂ = 26.98°C

how are molarity and volume related
these are the options
A They are directly related.
B They are inversely related.
C They are different units of dilution.
D They are different units of concentration.

Answers

Answer:

Molarity can be used to calculate the volume of solvent or the amount of solute. The relationship between two solutions with the same amount of moles of solute can be represented by the formula c1V1 = c2V2, where c is concentration and V is volume.

The relationship between Molarity and volume of a solution is : ( B ) They are inversely related

What is molarity ?

Molarity is the number of moles of solute in unit of volume of the solution ( usually per liter ). Molarity is calculated by dividing the number of moles of a solute ( n ) by the volume of the solution.

Molarity = n / v .

Therefore we can conclude that the relationship between Molarity and volume is that they are inversely related.

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Which represents a balanced nuclear equation?

Answers

Maybe factoring on the math equation might help or just search it up on YouTub

metals and their ore​

Answers

Answer:

Zinc

Zinc blende

(ZnS)

-----------------

Lead

Galena

(PbS)

-----------------

Mercury

Cinnabar

(HgS)

----------------

Copper

Copper glance

(Cu2S)

-------------------

Explanation:

Had to learn this for a test

Also, I plead the 5th

5. What type of pressure system____________and front____________are forming to have severe T-storms?

Answers

Answer:high pressure system and cold fronts

Explanation:

High pressure develops in areas where air cools and sinks. This usually causes fair weather with cool temperatures and few clouds.

Cold fronts occur when warm air is pushed up into the atmosphere by colder air at the ground. These fronts tend to move faster than the other types of fronts and are associated with the most violent types of weather such as severe and super cell thunderstorms, although any type of front can produce these same storms. After a cold front passes it is common to have clear skies and a dramatic change in wind direction on top of the cooler air associated with the front itself.

Write the balanced chemical equation for the reaction between aqueous sodium carbonate and
aqueous nitric acid.

Answers

Answer:

2HNO3 (aq) + Na2CO3 (aq) → 2NaNO3 (aq) + CO2 (g) + H2O (l)

Explanation:

This question is asking to write and balance an equation between between aqueous sodium carbonate (Na2CO3) and aqueous nitric acid (HNO3). The equation is as follows:

HNO3 (aq) + Na2CO3 (aq) → NaNO3 (aq) + CO2 (g) + H2O (l)

However, this equation is not balanced as the number of atoms of each element must be the same on both sides of the equation. To balance the equation, one will make use of coefficients as follows:

2HNO3 (aq) + Na2CO3 (aq) → 2NaNO3 (aq) + CO2 (g) + H2O (l)

Earth's surface is shaped and changed in many ways. Which of these can shape Earth's surface?

water

wind

ice

gravity

organisms (living things)

the sun

none of these

all of the above

Answers

Answer: All of the above!

Explanation:
Water- moves across soil and breaks down pieces of rocks
Wind- can blow materials around, such as rocks or sand. Also it can dry out soil.
Ice- carries broken rocks or soil to different places and can cause glacier erosion.
Gravity- thinking about it, earth is the one place with gravity so if gravity changed it can cause objects to move. Also it determines the shape of the earth because the center has more gravitational pull. This gives it a very round shape.
Organisms- more animals means increase of destruction of plants, which can lead to faster erosion.
Sun- the sun is very important. If the earth didn’t get any sunlight there wouldn’t be any life on the planet itself. Which makes it lack rocks, plants, weather, and the atmosphere.
And by that point it’s just not none of the above.

Water is said to be a good solvent for polar solutes because it has a negative end and a positive end. This explains why (IONIC/COVALENT) compounds dissolve easily in water. Highlight one​

Answers

yes thenpropert snd the negative end causes a iconic water fall

I need help fast answering these questions plzzz!! NO LINKS

Answers

Answer:

1. physical property

2. chemical property

3. physical change

hope this helps

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