Answer:
a ruler
Explanation:
What did John Dalton contribute to the understanding of the atom?
John Dalton contribute to the understanding of the atom that all matter was composed of atoms, indivisible and indestructible building blocks.
While all atoms of an element were identical, different elements had atoms of differing sizes and mass.
What is an atom?An atom is a particle of matter that uniquely defines a chemical element.
An atom consists of a central nucleus that is usually surrounded by one or more electrons.
Dalton's atomic theory was the first complete attempt to describe all matter in terms of atoms and their properties.
Dalton based his theory on the law of conservation of mass and the law of constant composition.
The theory states that all matter is made of atoms, which are indivisible.
(1) All matter is composed of tiny, indivisible particles, called atoms, that cannot be destroyed or created.
(2) Each element has atoms that are identical to each other in all of their properties.
Learn more about the atom here:
https://brainly.com/question/1566330
#SPJ2
The half life of iodine-125 is 60 days. What was the initial amount of iodine-125 if you have 4.5 grams after 360 days?
Answer:
288 grams
Explanation:
The amount of any radiative substance left after some time is calculated by
amount left = [tex]x/2^n[/tex]
where x is the initial amount of substance
n is the number of half lives
one half live is the time in which amount of substance reduce to half of its initial value.
------------------------------------------------------
amount left = 4.5 grams
half life of iodine-125 = 60 days
total time in which substance reduced to 4.5 grams = 360 days
thus,
number of half life in 60 days = 360/60 = 6
thus, there are period of 6 half lives
in each half life the amount of substance reduces to its previous half
let the initial amount be x grams
using the formula
amount left = [tex]x/2^n[/tex]
[tex]4.5 = x/2^6 \\ 4.5 = x/64\\x = 4.5*64 = 288[/tex]
Thus, 288 grams was the initial amount of iodine-125
Why do elements form chemical bonds?
Answer:
to make them more stable by filling up electrons
Which question can be answered by science?
Group of answer choices
Why should we help those less fortunate than us?
Which type of candy tastes the best?
Which kind of backpack do students purchase most often?
Why are children happy when they get home from school?
Answer:
C.
Explanation:
True/False (A= True & B =False) 46. Blood is a tissue. 47. Elastic cartilage is found in the ears, nose, epiglottis and larynx. 48. If you have a neoplasm you hope it is benign. 49. All cancers are neoplasms but not all neoplasms are cancer. 50. Plasma cells produce Histamine 51. The liver is one organ that can partially regenerate because it is made of epithelial cells 52. Keratin is a waterproofing protein found in epithelial cells
Answer:
46.A 47.B 48.B 49.A.50.A.51.B.52.B
The answer of the questions serially is true, false,false ,true,true,false and false where blood is a tissue which circulated by the pumping organ that is heart.
What is heart?
Heart is a muscular organ which is present in most of the animals , it is responsible for pumping blood via the blood vessels to the entire body.The blood which is pumped carries oxygen and nutrients along with it.Along with it on it's way back to heart it carries carbon dioxide to the lungs.
Heart has an approximate size of a closed fist and is present between the lungs in the middle compartment of the chest. It is divided in to for chambers , the upper chambers called atria and lower ones called ventricles.
The wall of the heart is made up of three layers : epicardium,myocardium and endocardium. It pumps blood with a rhythm which is determined by a group of cells which are called the pacemaker cells present in the sinoatrial node.
Learn more about heart,here:
https://brainly.com/question/16566688
#SPJ5
I need help with this ASAP PLEASE!! WILL MARK BRAINLIEST!!
Write the following value in decimal form
8.99 x 10^-7
Answer:
0.000000899
Explanation:
8.99x10^-7
move the decimal to the left 7 times.
0.000000899
Answer:
0.000000899
Explanation:
.,.......,.........
which contains the most amount of energy a glass of water at 20C or a glass of water at 80C. EXPLAIN ANSWER
Answer:
80C
Explanation:
As a substance gets hotter, or as a substance gets closer to the state of gas, the particles in the substance move faster, become more spread out and have more energy. This is why Gas has the most energy while solids have the least. Therefore, the hotter a substance is the more energy it has.
A glass of water at 80°C will have the most amount of energy
Explanation:
The temperature is defined as the degree of hotness and coldness of the object.It is a measure of the average kinetic energy of the particles of the object.The hotter the object, the higher will be the kinetic energy of the particles of the object, higher will be the value of temperature.The colder the object, the lower will be the kinetic energy of the particles of the object, lower will be the value of temperature.So, from this, we can conclude that glass with water at a higher temperature that is 80°C will have a higher amount of energy than a glass of water at 20°C.
Learn more about temperature here:
brainly.com/question/395469?referrer=searchResults
brainly.com/question/5427186?referrer=searchResults
How do you convert 34.6 kilograms to micrograms?
Also the Steps that got you that answer
Which one of the following is an alkane?
A. C2H4
B. C5H10
C. C3H8
D. C4H6
What is meant by the statement "Atoms are electrically neutral"?
Answer:
They have the same number of electrons as protons.
Explanation:
Atoms are electrically neutral means that all the charges within the atom are balance to equal neutral. An atom has the same number of protons as it does electrons, therefore the charge is neutral.
An ion has a different number of electrons than protons, making the ion either positively or negatively charged.
Answer:
Hi! I am currently taking AP Chemistry, I'll try to help you out.
That quote basically just means that the atom as a whole is not positively or negatively charged. Atoms are made up of protons, neutrons, and electrons. Neutrons are neutrally charged. Protons are positively electrically charged. And electrons are negatively electrically charged. In atoms, if there is an even number of protons and electrons, they can cancel each other's charges out, which results in the atom as a whole being electrically neutral.
Hope this helps! Feel free to mark me Brainliest if you feel this helped. :)
How many Protons, electrons, and neutrons are in Dysprosium?
EASY POINTS?
Answer:
Number of Protons - 66
Number of Neutrons - 97
Number of Electrons - 66
Explanation:
You're welcome :3
Which of the following are signs of a chemical change/reaction? Select all that apply.
1. A change in mass.
2. A change in energy (hot, cold, light)
3. A change in volume.
4. A change in odor.
5. A change in color.
6.A change in phase/state.
7. Boiling.
8.Melting.
9. Freezing.
Answer:
the answers are
Explanation:
5,6,7,8&9.
ANSWER FAST PLEASE
Maria’s class has learned how to drop an egg without breaking it. After 0.2 s, the kinetic energy of the falling egg is 0.5 J. If its mechanical energy is 2.3 J, what is its potential energy?
A. 1.2 J
B. 1.8 J
C. 2.8 J
D. 4.6 J
The Potential energy of the body is 11.8 Joules
The mechanical energy of the egg is given by the formula:
Mechanical energy = Potential energy + kinetic energy
Given the following parameters;
Mechanical energy = 2.3 JoulesKinetic energy = 0.5 JoulesFrom the formula:
Potential energy = ME = KE
Potential energy = 2.3 - 05
Potential energy = 1.8 Joues
Hence the potential energy of the body is 11.8 Joules
Learn more on mechanical energy here: https://brainly.com/question/24443465
People were surveyed to find out which part of the smore they like best. The data is as follows: 75% chocolate, 20% marshmallow, 5%. This information would be best displayed by aImmersive Reader
a. line graph
b. scatter plot
c. pie/circle graph
d. bar graph
Answer:
Pie/Circle graph
Explanation:
Pie/Circle Graphs are best for demonstrating parts of a whole, especially with percents.
how do convection currents form ?
Answer:
Convection currents occur when a fluid is near a heat source.
Explanation:
Heat sources provide energy to their surroundings. When fluid receives this energy, molecules inside it move around more, spacing out from each other and lowering the density.
We know from helium balloons that things with lower densities than their surroundings are pushed upwards. Therefore, the fluid close to the heat source moves upwards, as it is hotter than the rest.
As this fluid moves up, cooler molecules drift down, succumbing to gravity.
As hot molecules move up and further from the heat source, they cool down, and drop. As colder molecules drop and move towards the heat source, they heat up, and begin rising.
This results in a circular motion called a convection current. It is present in the strong winds at the seaside and in the magma in the Earth's mantle.
Which of the following is a measure of the amount of matter than object contained.
Weight
Mass
Volume
density
Answer:
weight = newton
mass = kilogram
volume = cubic meter
density = kilogram per cubic meter
Answer:
weight hghhiixjdhdhbdnfnfjfjjcndndnfmckkxkx
What happened to the rate of the reaction when the concentration was increased?
Explain the effect of concentration on reaction rate in terms of collision theory. Your answer should include at least four complete sentences.
Answer:
If you increase the concentration of a reactant, there will be more of the chemical present. More reactant particles moving together allow more collisions to happen and so the reaction rate is increased. The higher the concentration of reactants, the faster the rate of a reaction will be.
these are the last 2 questions on my assignment.... please help
1..orbit
2..7
I hope this was helpful
what role do particles play in exterting pressure?
Answer:
Pressure is an important physical quantity—it plays an essential role in topics ranging from thermodynamics to solid and fluid mechanics. As a scalar physical quantity (having magnitude but no direction), pressure is defined as the force per unit area applied perpendicular to the surface to which it is applied. Pressure can be expressed in a number of units depending on the context of use.
Explanation:
Probably not the best answer but hope this helps somewhat. :)
What are chemical sedimentary rocks formed from?
Answer:
Elements in fluids.
Explanation: They're formed from elements crystalizing in fluids (Like water.) For example limestone forms on the bottom of the ocean from calcium.
Answer:
The precipitation of ions in solution
Explanation:
How is a controlled experiment performed?
What strategies are involved in solving a science problem?
Answer:
In a controlled experiment, an independent variable (the cause) is systematically manipulated and the dependent variable (the effect) is measured; any extraneous variables are controlled. State what steps you will take to design an experiment to test your hypothesis. Complete the experiment. Make observations. Record what happened during your experiment.
Katie needs to measure water for a recipe she is using to cook dinner she should measure the liquid in...
A. inches
B. pints
C. pounds
D. yards
Answer:
pints
Explanation:
Answer:
B: pints
fl.oz.
Explanation:
If u have time pls help...
How is it that the chair is a solid, the water is a liquid, and the air you're breathing a solid if the entire room is the same temp? What about the substances make them different states at the same temperature?
Answer:
the internal force of attraction between the particle or molecules.
In solids the force is max.
In liquid it is intermediate.
And least in the gases..
The density of water is ____________.
Answer:
The density of water is 1 g/mL.
Explanation:
45.761 g - 42.98 = ___________
I believe your answer would be
2.781
5.) You bought a new car and estimated that your monthly payment would be $312. However, your actual
payment amount is $325. How much error was in your estimate?
If this decay has a half life of 2.60 years, what mass of 72.5 g of sodium 22 will remain after 15.6 years
Sodium-22 remain : 1.13 g
Further explanationThe atomic nucleus can experience decay into 2 particles or more due to the instability of its atomic nucleus.
Usually, radioactive elements have an unstable atomic nucleus.
General formulas used in decay:
[tex]\large{\boxed{\bold{N_t=N_0(\dfrac{1}{2})^{T/t\frac{1}{2} }}}[/tex]
T = duration of decay
t 1/2 = half-life
N₀ = the number of initial radioactive atoms
Nt = the number of radioactive atoms left after decaying during T time
half-life = t 1/2=2.6 years
T=15.6 years
No=72.5 g
[tex]\tt Nt=72.5.\dfrac{1}{2}^{15.6/2.6}\\\\Nt=72.5.\dfrac{1}{2}^6\\\\Nt=1.13~g[/tex]
Consider an element X that has two naturally occurring isotopes with the following percent abundances: the first isotope has a mass number of 84.912 and is 72.17% abundant; the second isotope has a mass number of 86.909 and is 27.83% abundant. What is the average atomic mass for element X?
Periodic Trends
PLEASE HELP ME! I WILL GIVE BRAINLIEST
a large office building is 1.07x10^2m long,31m wide. and 4.25x10^2m high. what id the volume?
If a large office building is 1.07 x 10^2 meters long, 31 meters wide. and 4.25 x 10^2 meters high, then the volume of the building would be 1409725 meters cube.
What is density?It can be defined as the mass of any object or body per unit volume of the particular object or body. Generally, it is expressed as in gram per cm³ or kilogram per meter³.
As given in the problem we have to calculate the volume of a large office building having the dimensions of 1.07 x 10 ^2 meters long, 31 meters wide, and 4.25 x 10^2 meters high.
The volume of the office building = length × width × height
=107 × 31 × 425
=140925 meters cube
Thus, the volume of the building would be 140925 meters cube.
To learn more about density from here, refer to the link;
brainly.com/question/15164682
#SPJ2