Answer:
Examples of measured numbers: The diameter of a coin, such as 10.2 mm. The weight of an object, such as 8.887 grams. The length of a pen, such as 12 cm.
Explanation:
Answer:
It completely depends on what you are measuring, what instrument you are using, and the uncertainty associated with your measurement.
Explanation:
When expressing a measurement, there is always going to be a part that you know, and a part that you guess. They both make up known numbers collectively called significant figures (commonly shortened to "sig figs"). For instance, imagine you are measuring the length of a pencil. Let's say it is a typical ruler with divisions of 0.1 cm (picture for reference). You measure the pencil, and to your eyes it looks like it is about 9 cm and 5 small tick marks (so, 0.5 cm), so we'll call that 9.5 cm. Now, this is a known value, so you are certain that it is a least 9.5 cm. However, it may be true that there is one more decimal place that can be known. The general rule is that you want to add one more uncertain digit to the rightmost side of the number, and how many digits depends on the divisions of the instrument. Our ruler has divisions of 0.1 cm (the small tick marks), and so we will go one more place out, and add another digit. Now, let's say our eyes are pretty good, so let's say it's 9.5 cm, and then add that one uncertain digit, a 0 to the smallest division of 0.1, so, 0.10. The final measurement we record is 9.50 cm. Now, it may seem like we are simply guessing or even being unreasonable in our assessment of how long this pencil is. I can promise you that not knowing the actual measurement of this pencil will not make a spaceship crash because of a specification that was not the "right measurement". For those life-or-death measurements, much more precise measurement machines are used; this is just a pencil. Also, it would be unreasonable to say that it is 9.500000 cm or 9.500001 cm. We do not have that kind of certainty with this ruler, only divisions of 0.1 cm, so we can only estimate out to one more decimal place.
In short, find the smallest division of a ruler or whatever device (like a chemical beaker) you are using, and then add one uncertain digit to the end of that. If it's 0.1 cm, then add one digit to that. (example: 5.6 --> 5.63; 3 because that is what it looks like on the ruler). If it's 1 cm, then add an extra .1, so the measurement is 1.1 cm. And of course, it's not always cm you are using, that was just an example. Best of luck!
*
Why does the mass of a substance remain the same after a chemical reaction?
Is your breath becoming visible on a cold day a physical change
Answer:
no
Explanation:
it is condensation not physical change
HELLLPPPPPPPPPP
Match each substance with either acid or base.
Lemon juice:
Baking soda:
Ammonia:
Vinegar:
PLZ DON'T GUESS THE ANSWER
Answer:
Lemon Juice - Acid
Baking Soda - Base
Ammonia - Base
Vinegar - Acid
LOTS OF POINTS WILL GIVE BRAINLIEST!!
Plot a graph of relative atomic mass against boiling point for the
elements in Group 0.
Answer:
I found this, hope it works
Explanation:
As the mass of the noble elements increases the boiling point gradually decreases and the graph of the two parameters is a straight line graph with downward slope.
What is an element?It is defined as a substance which cannot be broken down further into any other substance. Each element is made up of its own type of atom. Due to this reason all elements are different from one another.
Elements can be classified as metals and non-metals. Metals are shiny and conduct electricity and are all solids at room temperature except mercury. Non-metals do not conduct electricity and are mostly gases at room temperature except carbon and sulfur.
The number of protons in the nucleus is the defining property of an element and is related to the atomic number.All atoms with same atomic number are atoms of same element.
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If you mix aqueous solutions of potassium nitrate and iron(II)sulfate what will be the precipitate, if there is one at all?
Answer:
No one will precipitated because these all are soluble in water
Explanation:
2KNO3 + FeSO4 -----> K2SO4 + Fe(NO3)2
Please help me 14 points!
Answer:
2
Explanation:
What kind of cell has a nonspontaneous voltage?
An electrolytic cell
A dry cell
A wet cell
A voltaic cell
Answer:
dry cell
Explanation:
because it stops when salt distribution becomes equal as bridge is not added
Answer:
a
Explanation:
a p e x :)
Which of the following correctly shows the relationship, in terms of number of particles, of the three substances?
A. 1 mole of water < 1 mole of helium < 1 mole of aluminum
B. 1 mole of aluminum = 1 mole of helium = 1 mole of water
C. 1 mole of aluminum < 1 mole of helium < 1 mole of water
D. 1 mole of helium < 1 mole of aluminum < 1 mole of water
The correct option which shows the relation between particles of the three substances is 1 mole of aluminum = 1 mole of helium = 1 mole of water.
What is a particle?
A particle is a small part of matter.
The term refers to particles of all sizes, ranging from subatomic particles like electrons to visible particles like dust particles floating in sunlight.
The relationship of a number of particles of the substance can be calculated by Avogadro's law
Thus, the correct option is B. 1 mole of aluminum = 1 mole of helium = 1 mole of water
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how many moles of oxygen atoms are in one mole of the molecule Ca5(PO4)3OH?
Answer:
13
Explanation:
There are 13 moles O in a mole of Ca5(PO4)3OH because there are 13 oxygen atoms in every molecule of Ca5(PO4)3OH. Convert moles oxygen to number of atoms of oxygen. One mole is 6.022*10^23, so your conversion factor would be 6.022*10^23 atoms O/mol O.
Describe the relationship between frequency and wavelength in your own words
What is the molar mass of MgI2
Answer:
278.1g/mol
Explanation:
To find the molar mass of the given compound, we must know the atomic mass of the elements within the compound.
Atomic mass of Mg = 24.3g/mol
Atomic mass of I = 126.9g/mol
So;
Molar mass = 24.3 + 2(126.9) = 278.1g/mol
The molar mass of the compound is 278.1g/mol
How many moles of gas would be present in a gas trapped within a 0.1 L vessel at
25.0 °C at a pressure of 2.50 atm?
Answer:
Number of moles = 0.01 mole
Explanation:
Given data:
Volume of gas = 0.1 L
Number of moles = ?
Temperature of gas = 25.0°C
Pressure of gas = 2.50 atm
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.
25+273K = 298 K
by putting values,
2.50 atm × 0.1 L = n × 0.0821 atm.L/ mol.K × 298 K
0.25 atm.L = n × 24.47atm.L/ mol
n = 0.25 atm.L /24.47atm.L/ mol
n = 0.01 mol
What coefficient should be placed before 02?
2S+ __02 → 2S03
Explanation:
[tex]\tt{2S+6O_2\implies{2SO_3} }[/tex]
Which process is an example of a chemical change?
a. cooking a steak
b. chopping a tree
c. heating a cup of tea
d. drying clothes in the dryer
Answer:
A is the closest thing. You change the composition of the steak. You don't in any of the others.
Explanation:
Usually when you cook something, you are doing something to the composition of the object being cooked. A steak might not be obvious, but boiling an egg should be.
Chopping a tree is something physical. You are removing mass in such a way that the tree will fall. There's nothing chemical about that.
Heating a cup of tea looks like it might be chemical. After all steam is sometimes given off which looks like it is chemical. It's not. The water in the tea is just changing phase.
Drying clothes in a dryer. Again, this looks like something might have changed. After all the mass of the clothes just became less. But all you are doing is separating two masses (leaving one of them behind).
This biome has extremely cold winters and short, mild summers. It has no trees, only low-growing plants with short root systems because of its frozen soil
called the permafrost. It is covered by snow for most of the year. Animals that live here must have wide paws or hooves to walk through the frozen mushy.
soil. This biome is known as the_________
A. Tropical rainforest
B. Taiga
C. Deciduous Forest
D. Desert
E. Grassland
F. Tundra
can someone show me the work on 3-8?
3. 426 g
4. 413.4 g
5. 1328.4 g
6. 192.4 g
7. 106.4 g
8. 0.617 mol
Further explanationGiven
moles and mass
Required
Conversion mole to gram
Solution
General formula :
mole (n) = mass : MW
3. 6 moles Cl₂(MW = 71 g/mol) :
= 6 moles x 71 g/mol
= 426 g
4. 5.3 moles CaF₂(MW=78 g/mol)
= 5.3 mol x 78 g/mol
= 413.4 g
5. 8.2 moles FeCl₃(MW=162 g/mol)
= 8.2 mol x 162
= 1328.4 g
6. 2.6 moles Li₂CO₃(MW=74 g/mol)
= 2.6 mol x 74 g/mol
= 192.4 g
7. 3.8 moles N₂(MW=28 g/mol)
= 3.8 mol x 28 g/mol
= 106.4 g
8. 100 g FeCl₃(MW=162 g/mol)
= 100 g : 162 g/mol
= 0.617 mol
how many moles are represented by 3.01x10^23 helium atoms
a. 1 mole
b. 0.50 moles
c. 0.75 moles
d. 5 moles
Answer:
b. 0.50 moles
Explanation:
To solve this problem we use Avogadro's number (6.023x10²³ atoms/mol).
By dividing the number of atoms (or molecules) by that number, we can calculate how many moles they represent.
3.01x10²³ atoms ÷ 6.023x10²³ atoms/mol = 0.50 molesSo the answer is option b. 0.50 moles.
Methane is a gas that easily catches fire. This statement is describing a _____.
Answer:
I believe the answer would be chemical reaction.
How many atoms are in 162.0 g of magnesium?
Answer:
3,938.22
Explanation:
(correct me if I'm wrong)
Which of the following is a monoatomic molecule? *
Phosphorus
Sulphur
Neon
chlorine
phosphorus
Explanation:
other are diatomic
Cl2
S2
Ne2
Which of the following reactions would have a decrease in entropy?
A. 2H20(g) → 2H2(g) + O2(9)
B. 2503(9) ► 2502(g) + O2(g)
C. 2NH3(9) ► N2(g) + 3H2(9)
D. 2NO2(g) → N204(9)
Answer:
D. 2NO2(g) → N204(9)
Explanation:
A p e x
2NO[tex]_2[/tex](g) → N[tex]_2[/tex]O[tex]_4[/tex](g) reactions would have a decrease in entropy. Therefore, the correct option is option D.
What is entropy?Entropy is a measureable physical characteristic and a scientific notion that is frequently connected to a condition of disorder, unpredictability, or uncertainty. From classical thermodynamic, where it was originally recognized, towards the microscopic explanation of nature within statistical physics, the name and concept are employed in a variety of disciplines.
It has numerous applications in physics and chemistry, biological systems and how they relate to life, cosmology, economics, society, weather science, and information systems, especially the exchange of information. 2NO[tex]_2[/tex](g) → N[tex]_2[/tex]O[tex]_4[/tex](g) reactions would have a decrease in entropy.
Therefore, the correct option is option D.
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how do you find out which molecule out of two is more polar
Answer:
Check the electronegativities of the atoms involved in each bond. The greatest difference in electronegativity will correspond to the most polar bond.
how many atoms are in 2.45 moles of hydrogen
Answer:
There are 1.4754246675000002e+24 atoms of Hydrogen within the measurement of 2.45 moles of hydrogen!
Explanation:
How do you measure density?
Density over mass
Mass over volume
Volume over density
Mass over density
Answer:
Mass over Volume........
Making Sense
1. School bus drivers are extra careful when they cross railroad tracks. They stop before they cross railroad tracks to be sure that there is no
train coming. Yet, trains typically move more slowly through towns than cars do. If trains usually move more slowly than cars, why can
they do more damage if they hit something in their path?
=
2
11
B
1
GO
III
un
III
X2
Saved January 15, 2021 07:35:00 PM
Answer: I think that trains move faster then cars! Buttt, The trains are much stronger and bigger, then cars or trucks. Even if they move slowly they can still crush something smaller then them.
Explanation: ( didnt really understand the question, but i tried)
why is hardness important in identifying minerals
Most polyatomic ions are cations.
TRUE
FALSE
The answer is False.
23) What is the volume of 2.454 x 1024 atoms of nitrogen gas at STP?
[a] 1.096 x 1023 L
[b] 6.595 x 1048 L
[c] 2.241 x 1026 L
[d] 91.31L
Answer:
d) V = 91.3 L
Explanation:
Given data:
Volume of nitrogen = ?
Temperature = standard = 273.15 K
Pressure = standard = 1 atm
Number of atoms of nitrogen = 2.454×10²⁴ atoms
Solution:
First of all we will calculate the number of moles of nitrogen by using Avogadro number.
1 mole = 6.022×10²³ atoms
2.454×10²⁴ atoms × 1 mol / 6.022×10²³ atoms
0.407×10¹ mol
4.07 mol
Volume of nitrogen:
PV = nRT
1 atm × V = 4.07 mol ×0.0821 atm.L /mol.K ×273.15 K
V = 91.3 atm.L /1 atm
V = 91.3 L
Applying a force for a longer time increases the change in
(select all that apply)
Weight
Gravity
Velocity
Mass
Momentum
Answer:
velocity and momentum
Explanation:
as you exert force, the object accelerates, hence, its velocity increases.
since momentum is mass times velocity, the momentum increases too
Please be reminded, this answer may not be 100% correct
When the force should be applied for a long time so it increases the change in velocity and momentum
What is velocity and momentum?The momentum of the object should be equivalent to the object mass times with the object velocity
Here
p = mv
Here p means momentum
m means mass
v means velocity
Here the momentum should be directly proportional to the mass of the object and for the velocity of the object also.
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why water is not used as a thermometric substance
Answer:
Water can be used as the thermometric liquid. It expands and contracts with temperature so it can be used. It's just not a very good choice because: It's thermal expansion is not very large compared to other liquids like mercury.
Explanation:
Hope this help