Answer:
mass number
Explanation:
The sum of the protons and neutrons in an atom equals the mass number of such an atom.
Mass number is the mass of an atom. The mass of an atom is concentrated in the nucleusThe particles in the nucleus are the protons and neutrons.So;
Mass number = number of protons + number of neutrons.
How much heat is required to raise the temperature of a 6.21 g sample of iron from 25.0 oC to 79.8 oC?
Answer:
151.1J
Explanation:
Given parameters:
Mass of iron = 6.21g
Initial temperature of iron = 25°C
Final temperature of iron = 79.8°C
Unknown:
Amount of heat = ?
Solution:
The amount of heat require to cause this temperature can be determined using the expression below;
H = m c (T₂ - T₁)
H is the amount of heat
m is the mass
c is the specific heat capacity
T is the temperature
Specific heat capacity of iron 0.444J/g°C
Insert the parameters and solve;
H = 6.21 x 0.444 x (79.8 - 25)
H = 151.1J
Directions: Read through each scenario and identify the independent variable, dependent variable, and the control.
Question 1
1 pts
Rob is in charge of waxing the floor at the local mall. He wants to test a new brand of floor wax called
Squeaky Clean. Rob waxes 20 floor tiles with Squeaky Clean and 20 tiles with the original wax brand.
After one week he counts the number of scratches on the floor. What is the independent variable?
number of floor scratches
brand of floor wax
20 tiles with original brand wax
Answer:
The correct answer is - brand of floor wax.
Explanation:
The independent variable is the variable or the factor in an investigation which is manipulated or change in the experiment and affects the dependent variable and produces a various result.
In this investigation, there are different brands of the floor was are the independent variable as they are changed to see the effect on the scratches on the floor on 20 tiles for each brand.
Which method of heat transfer is the person in the picture below most worried about?
Radiation
Conduction
Convection
Answer:
Radiation ...........
[tex]\huge\boxed{Conduction}[/tex]
_____________________________________Conduction:Conduction is the transfer of heat when two things come in contact with each other. The energy transfer is from hotter body to the colder body.
x---------------------------------------------x
Fire Walking:There is a trick behind fire-walking. When the coal burns, after sometime there is a layer of ash on the surface of the coal which blocks the radiation. So the transfer of heat is not possible from radiation. Conduction is the only way possible. The person's feet and coal both are poor conductor of heat so if we walk quickly i.e. there is minimal time of contact with the coal, it will just feel a little warm. As the person start walking on the coal, It has to do it quickly, that way Person will feel its sole warming up but it is not that hot because of the layer of ash and poor conductance, after few steps the ash also sticks on to the sole of the person which makes kind of double layers of ash. So the only way for heat transfer is CONDUCTION.
_____________________________________Best Regards,'Borz'An isotope of Cesium -137 has a half-life of 30 years. If 1.0 g of Cesium – 137 disintegrates over a period of 60 years, how many grams of Cesium- 137 would remain?
Answer:
Explanation:
Radioactive decay follows the equation:
Ln [A] = -kt + ln [A]₀
Where [A] is amount of isotope after time t: Our incognite,
k is rate constant: ln 2 / Half-life = 0.0231 years⁻¹
t are 60 years
[A]₀ is initial amount of isotope: 1.0g
Replacing:
Ln [A] = -kt + ln [A]₀
Ln [A] = -0.0231 years⁻¹*60 years + ln 1.0g
ln [A] = -1.386
[A] = 0.25g
Please help me what is the answer
There are 20.8 moles of propanol
Further explanationThe mole is the number of particles(molecules, atoms, ions) contained in a substance
1 mol = 6.02.10²³ particles
Can be formulated
N=n x No
N = number of particles
n = mol
No = Avogadro's = 6.02.10²³
1.2 x 10⁵ molecules of propanol
[tex]\tt \dfrac{1.25\times 10^{25}}{6.02\times 10^{23}}=20.8~moles[/tex]
2. What properties do all acids have?
3. Why should you never use taste as a method for testing an unknown substance?
4. What is used to detect the presence of acids?
10. What can you use to detect the presence of a base?
11. What are some common bases that we use every day?
12. How does an antacid help reduce heartburn?
13. What happens when acid and base are mixed
14. What is used to determine the pH of a substance?
15. Describe how the pH scale works. In other words, what is it actually measuring?
17. Why is pH important to our environment?
18. Describe how salt is formed.
Pls help!!!!!
A geologist was looking at a new
mineral they found. The mineral
sample was gray, non-metallic, had
density of 3.8 g/mL, and a volume
of 48.3 mL
Of the observed properties listed
below, which is considered to be an
extensive property?
A Gray
B Metallic
C Density
D Volume
Answer:
D. Volume
Explanation:
Properties mentioned in the question;
colour = gray
Nonmetallic
Density = 3.8 g/mL
Volume = 48.3 mL
Of the mentioned, which is extensive ?
Extensive properties are those properties that are proportional to the amount of substance present.
The correct option is D. Volume. The other properties do not change with increasing or decreasing amount of the mineral
A beaker filled with 100 ml of water has an initial temperature of 23 degrees Celsius. After the beaker has been heated, the final temperature is 100 degrees celsius. The final volume of the water is 85.32 ml. After reaching the final temperature, there are bubbles throughout the water. What is this an example of?
Answer: The temperature of a beaker of water is 318.2 K.
Explanation:
Multiplying the temperature in Celsius by tells us how many Fahrenheit degrees above the freezing .
The growth of a plant toward light is called _____.
phototropism
tropism
geotropism
It's called phototropism
Answer:
The answer is (Phototropism)
I WILL GIVE BRANLIEST HELP HELP HELP THE SUBJECT IS ACTUALLY SCIENCE What factor is a mushroom in an ecosystem? Abiotic or Biotic?
Answer: The answer is biotic
Explanation:Mushrooms are biotic because they are living things. Abiotic means non living, so these are factors in the environment that influence a living thing's life and chance of survival
Answer: jdusjzj bacteria germs
Explanation:
HELP ME PLEASE ! I NEED HELP !
Which statement best completes the diagram?
Mexican culture
Most people live in
urban areas.
The most widely
spoken language is
Spanish
?
A. The most important literature is nonfiction
B. The most popular foods are vegetarian,
C. The most common religion is Catholicism.
D. Most people work as farmers.
Answer:
The answer is (c)
Explanation:
Answer:
C. The most common religion is Catholism.
Explanation:
I'm taking the quiz rn.
Below is a phase diagram for Carbon Dioxide. Use this diagram to answer the following question.
In this example we will start the Carbon Dioxide out at a temperature of -20oC and 1 atm of pressure. If the pressure was raised to 100 atm of pressure while still staying at -20oC, what phases would the Carbon Dioxide change between?
1. What part of the human body has the same role as the power source in a computer?
2.What part of the human body has the same role as the keyboard or the mouse on a computer?
Answer:
The heart
Hand
Explanation:
The part of the human body that has the same role as the power source in a computer is the heart. A power source in a computer provides energy that powers the whole system.
The human heart provides the pumping action for the circulatory system. Just like current passes through wires in a computer by energy from the power source, the human heart pumps blood throughout the body in a like manner. Without the pumping action of the heart, the human body is dead.Also, keyboard and mouse are input devices. They are used to give instruction and perform certain tasks on the computer system.
The human body can also carryout tasks by using the hand. Objects are moved from one place to another just as you drag an icon using the mouse. We type word processors using information from the keyboard, also, we are able write using pen on paper.Help please If there are 10 moles of HCl gas occupying 15L at 350°C, what is the pressure? Be sure to show the setup and
the final answer and unit.
Show Your Work
Answer:
P = 34.1 L
Explanation:
Given data:
Number of moles = 10 mol
Volume occupy = 15 L
Temperature = 350°C
Pressure of gas = ?
Solution:
The given problem will be solve by using general gas equation,
PV = nRT
P= Pressure
V = volume
n = number of moles
R = general gas constant = 0.0821 atm.L/ mol.K
T = temperature in kelvin
Now we will convert the temperature.
350+273 = 623 K
by putting values,
P×15 L = 10 mol ×0.0821 atm.L/ mol.K ×623 K
P = 511.48atm.L/15L
P = 34.1 L
What is an important part of the endocrine system that acts as a chemical messenger?
hormones
arteries
spinal cord
neurons
When the following equation is balanced, what is the coefficiant for Br?
___I2 +___NaBr rightwards arrow___NaI +_?_Br2
A.
6
B.
3
C.
1
D.
2
1 points
QUESTION 10
The previous question is an example of what type of chemical reaction?
A.
Synthesis
B.
Decomposition
C.
Single Re-Placement
D.
Double Re-Placement
Answer:
1. A 2. C
Explanation:
because it just is
When naming acids the prefix hydro- is used when the name of the acid anion ends in___
Answer:
hydrochloric acid
Explanation:
These anions usually have the ending “-ide.” As acids, these compounds are named starting with the prefix “hydro-,” then adding the first syllable of the anion, then the suffix “-ic.” For example, HCl, which is hydrogen and chlorine, is called hydrochloric acid. More complex acids have oxygen in the compound.
How to do this question plz answer me
Answer:
dissolved
Explanation:
The figure shows sodium chloride is in solution. It gets that way by being dissolved.
paragraph on water cycle
Answer:
The water cycle or hydrologic is a continuous cycle where water evaporates, travels into the air and becomes part of a cloud, falls down to earth as precipitation, and then evaporates again. ... These areas are usually close to oceans or large bodies of water that allow more water to evaporate and form clouds.
Explanation:
how is a solute and a solvent different
Please help brainiest is award!
Which of the following does not apply to water molecules?
Water molecules are polar
Water has cohesive properties
Water is less dense as a solid than a liquid
Water is not a very good solvent
Answer:
It is the last one.
Explanation:
Water molecules are polar, they have cohesive properties, and water is less dense when it is solid than when it is a liquid, that is why ice floats in liquid water. However, water is a very good solvent, it can dissolve many solids, including sugar, salt, and other hydrophilic substances.
Question 4 of 10
What is the molarity of a solution of 3 moles (mol) of FeBr3 in 1/2 L water?
A.
3 mol/2L
B.
2L/3 mol
C.
0.5L/3 mol
D.
3 mol/0.5 L
SUBMIT
Answer:
B
Explanation:
Answer:
D. 3 mol/0.5 L
Explanation:
Just took the quiz
What are the coefficients that will balance the skeleton equation below?
___GaF3 +___KCN rightwards arrow___Ga(CN)3 + ___KF
A.
1, 3, 1, 3
B.
3, 1, 3, 1
C.
1, 1, 1, 3
D.
1, 3, 3, 1
1 points
QUESTION 6
The previous question is an example of what type of chemical equation?
A.
Synthesis
B.
Decomposition
C.
Single Re-Placement
D.
Double Re-Placement
1, 3, 1, 3
Explanation:
Ga - one on both sides
F - three on both sides
CN - three on both sides
K - three on both sides
But remember that CN was being multiplied by 3 on the right side already, meaning GA(CN)3 didn't mean a coefficient.
Answer:
Double re-placement
The two metals switched dance partners, that means it's a double.
Calculate the percent composition of C6H12O6
Answer:
Did you just let your cat walk on your keyboard? XD
Could you explain this a bit better please?
I'll answer the question in the replies of this comment if you can give me a bit more information.
Explanation:
May I have brainliest please? :)
Why should a hypothesis be testable?
A. It must be testable in order to be found true or false.
B. It must be testable for the outcome to be predictable.
C. It must be testable for other scientists to consider it reliable.
D. It must be testable if it is to become a scientific theory.
How many electrons are located in the outermost energy level in the Bohr model of a boron atom? hint it not 4
4
3
2
1
Which models of the atom does the experimental evidence from Bohr's hydrogen experiment support? Explain why these models are compatible with the experimental results.
The models are Daltons, Thompsons, and Rutherfords
Answer:
Rutherfords
Explanation:
The model of the atom supported by Bohr's hydrogen experiment is the Rutherford's model of the atom.
Rutherford through his experiment on gold foil suggested the atomic model of the atom. The model posits that an atom has a small positively charged center(nucleus) where nearly all the mass is concentrated.
Surrounding the nucleus is the large space containing electrons. In the Bohr's model of the atom, he suggested that the extranuclear space of the atom is made up of electrons in specific spherical orbits around the nucleus.Butane and methyl propane are an example of a pair of
Momentum is mass times
A. acceleration
B. velocity
C. distance
B. velocity
This is the answer