Answer:
25 protons, 25 electrons, 30 neutrons. ......... manganese is the identity
Explanation;
x = atomic number -# of protons
The number of neutrons = x + 5
The mass number (sum of protons + neutrons) = 55.
x + (x + 5) = 55
2x + 5 = 55
2x = 50
x = 25; atomic number 25 = manganese (Mn)
so ;
25 = Protons
30=Neutrons
25=Electrons
Which of these is an example of a physical change?
O a banana ripening in the air
hydrogen burning in the air
zinc reacting with an acid
O liquid water turning into vapor
water into vapor is the answer
Answer:
liquid water turning into vapor
Explanation:
because physical changes alter only the size
An electron jumps down from the fourth energy level to the first energy level and releases a light wave of 10.8 nm in wavelength. Determine the energy level value for the fourth energy level for the atom
Answer:
-20.2 * 10^-18 J
Explanation:
From;
E = hc/λ
h= planks constant = 6.6 * 10^-34 Js
c= speed of light = 3 * 10^8 ms-1
λ = wavelength = 10.8 * 10^-9 m
Substituting values;
E = 6.6 * 10^-34 * 3 * 10^8/ 10.8 * 10^-9
ΔE = -1.8 * 10^-17 J
But for ground state E1=−13.6eV or -2.176 * 10^-18 J
From;
ΔE = E4 - E1
E4 = ΔE + E1
E4 = (-1.8 * 10^-17) + (-2. 176* 10^-18)
E4 = -20.2 * 10^-18 J
Suggest whether water freezing is an endothermic or exothermic process. Can you explain your suggestion?
An atom of an element has 2 electrons in the 1st energy level and 5 on the 2nd energy level what element is it ?
the element is nitrogen
5+2=7
Explain what it means to have a positive percent error value and a negative percent value.
Answer:
The error of an experiment is the difference between the experimental and accepted values. If the experimental value is less than the accepted value, the error is negative. If the experimental value is larger than the accepted value, the error is positive.
Explanation:
I hope that helped if it did mark me brainlest! i really need it :(
electronegativities of elements from Period 3 and Group 17. Fill in the missing values in the table so you can compare the electronegativities of the elements. After the table is filled in, compare the values in each column. A = B = C =
Answer:
A = 3.16
B = 1.31
C = 0.93
Explanation:
Which event most likely occurs at point V?
cooling
erosion
heating
melting
Answer: cooling
Explanation:
Answer:
cooling
Explanation:
Select all that apply. Using your periodic table of the elements which chemical symbols indicate an element?
Question 5 options:
O
I
i
Ca
Answer:
O, I, Ca
Explanation:
Can be a solid,liquid,or gas A)Metal B)Nonmetal C)Both
Answer:
I think it's B. Nonmetal
(I'm so sorry if it's wrong)
Hope this Helps!
Answer:
I personally think it's both I'm sorry if this is wrong
How can a mixture be separated?
Answer:
Mixtures can be physically separated by using methods that use differences in physical properties to separate the components of the mixture, such as evaporation, distillation, filtration and chromatography.
How many atoms of each element are in one molecule of 2-heptanone
Answer:
A chemical structure of a molecule includes the arrangement of atoms and the chemical bonds that hold the atoms together. The 2-HEPTANONE molecule contains a total of 21 bond(s) There are 7 non-H bond(s), 1 multiple bond(s), 4 rotatable bond(s), 1 double bond(s) and 1 ketone(s) (aliphatic).
Answer:
Explanation:
CH3 provides 1 Carbon
C4 provides 4 carbons
COC provides 2 more
Total 7 Carbons
======================
COCH3 Provides 1 Oxygen
======================
CH3 provides 3 Hydrogens
C4H8 provides 8 hydrogens
COCH3 has 3 more hydrogens
Total 14 hydrogens
The answer should be B.
You should note that there are no brackets which means you only need to read the small numbers going down behind each element. You might have to read that sentence a could of times, but it is important to know.
Use the equation below to solve the problem that follows.
2H2 (g) + O2 (g) → 2H2O (g)
When David reacts 13.8 grams of hydrogen gas with excess oxygen, 87.0 grams of water are formed. Calculate his percent yield of water.
Answer: 142.8%
Explanation:
13.8g H2 * (1 mol H2 / 2 g H2) * (2 mol H2O/ 2 mol H2) * (18 g H2O/1 mol H2O) = 124.2 g H2O
we just calculated our theoretical amount that should be formed and we are given the actual
percent yield: actual/theo * 100% = 124.2/87 * 100% = 142.8%
WILL GIVE BRAINLIEST Pam and Caroline determined the mass and volume of a piece of metal to be 34.16 g and 11.3 mL respectively. Determine the density of the metal. (Please show work and use significant figures.
Answer:
0.303kg/m
Explanation:
Density=m/v where m is mass
and v is volume
we then convert m in grams to kg
= 34.16/1000
=0.0342kg
converting ml to m
=11.3/100
=0.113m
then density=0.0342/0.113
=0.303kg/m
Describe how the molecular models you assembled are similar to real molecules.
They model how real molecules are.
Answer:
Atoms models are bigger but they don not match the true or positive way of atoms. to make them visible scientists make their models that resembled with the real ones.
Explanation:
Molecules are microscopic entities and only can be seen under a microscope.
In geotropism, give examples of a positive and a negative response in a seedling?
Answer:
I don't know that question answer because I am in 7 class so mind it
Answer:
Positive Geotropism means growth of the plants towards the Gravitational force. e.g.It means When a plant's root grows towards Gravitational force . It is positive geotropism. Negative Geotropism means growth of the plant against the Gravitational force. e.g. When a plant's steam grows towards sunlight.
Explanation:
When will heat transfer stop?
Answer:
Heat
Explanation:
Heat will always flow from the warmer object to the colder object. The heat transfer will stop when the two objects are at the same temperature and reach thermal equilibrium.
Hope this helps!
Answer:
when both object are the same temperature
Explanation:
in any study of energy, energy conversion is not important. true false
Answer:
I think its false
Explanation:
Any energy is important
Hope this helps <3
Answer:
In any study of energy, energy conversion is not important. Heat energy that is lost cannot usually be used to produce work.
Explanation:
Hope this helps!
If so, please mark BRAINLIST!!
thx
What is Constituent Element?
Answer:
hope it helps...
Explanation:
a constituent element, material, etc.; component. a person who authorizes another to act in his or her behalf, as a voter in a district represented by an elected official. Grammar. an element considered as part of a construction. Compare immediate constituent, ultimate constituent.
If this helped please comment...
why organic compounds have a slow rate of reaction
Answer:
first help me plz plz
Explanation:
coz i hate chemistry
5. Name the compound which contain Strontium, Fluorine, and Oxygen.
Options:
Strontium fluorate
Strontium fluoride
Strontium chlorate
Strontium fluorine
what is 43 mg into grams
Hello there :) here are the answers and hope you a GREAT Thanksgiving :)
0.043 grams
how does voltage work in a circuit?
Answer:
Voltage is the pressure from an electrical circuit's power source that pushes charged electrons (current) through a conducting loop, enabling them to do work such as illuminating a light.
Explanation:
I hope this is right i found it off a website called fluke!
A baseball is thrown a distance of 20 meters. What is its speed if it takes 1 second to cover the distance?
Use the drop-down menus to identify the order of these images for the formation of our solar system.
Answer:
Explanation:
Help please! Tell me which one goes where.
Answer:
human-F
chicken-D
rabbit-E
tortoise-C
salamander-B
fish-A
Explanation:
hope this helped!!
I tried my best!!
please mark me as brainliest
HAVE A GREAT DAY <3
Answer:
D Tortoise
B Salamander
A Fish
C Chicken
F Human
E Rabbits
Explanation:
I Really have an Explanation
Which is the best example and explanation that a physical change has occurred?
:answer question number 8
Answer:
Weight
Explanation:
Weight changes because the moon's gravity is different from the Earth's. Mass is always the same. Volume remains the same. Density also remains the same. Hope my answer is correct! If there is a lot of explanation, you can give a brainliest to my answer.
What happens to the energy release of an exothermic reaction?
1.It increases the bond energy of the reactants.
2.It is released to the surroundings.
3.It raises the temperature of the reactants.
Answer:
2.It is released to the surroundings.
Explanation:
In an exothermic reaction, the energy released is to the environment. At the end of the reaction, the surrounding becomes hotter than the system where the reaction is taking place.
Heat is liberated to the surrounding in an exothermic change. At the end of this change, the surrounding becomes hotter. Examples are combustion, dissolution of substances, etc.PLZ ANSWER! MULTIPLE CHOICE!! MUST BE CORRECT!! I CANNOT GET THIS WRONG.
How do I find the formula for Phosphorus Tetroxide
Urgent help plzzzzzz?!!!!!!!!!!!
Answer:
Explanation:
For 4 all you have to do is take the -log(H3O+) and then use your PH values to identify if it's acidic or basic
a. 2.06 - acidic
b. 8.4 - basic
c. 6.67 - acidic
d. 5.85 - acidic