Help!!!!

I can’t understand this question

Answer:

Pure substances are substances that are made up of only one kind of particles and has a fixed or constant structure. Pure substances are further classified as elements and compounds. An element is a substance that consists of only one type or kind of atom

Answer:

define the term pure substance​ :

A pure substance does not have to be of a single element or compound, This can either be one single element or one single compound, but every sample of this substance that you examine must contain exactly the same thing with a fixed, definite set of properties

Explanation:

Answer:

All of them derive from a common ancestor. They each share something in their DNA that ties into their past selves, which were more closely related. As they evolved, they became more and more distant, but we can still trace them back to the olden days.

Also they all have scales.

Hope this was at least semi-useful.

Answer:

As you noticed, the percent-error formula needs you to use a value in the ... The actual absolute zero is 275C below my coldest recorded value. ... The only way your calculations makes sense is you're trying to calculate how ... Next, I'll interpret "I found that AZ is at -258°C" as "I calculated AZ to be 260 degrees below 2°C".

Explanation:

The experimental error will be 8.95%

The formula  used for calculating the percentage error is expressed as:

[tex]\% error=\frac{|exp. \ value - actual \ value|}{actual \ value} \times 100[/tex]

Given the following parameters

Actual value = −273.15 degrees Celcius

Let the experimental value be 300 degrees Celcius (since we are not given)

[tex]\% error=\frac{|300 - 273.15|}{300} \times 100\\\% error=\frac{|26.85|}{300} \times 100\\\% error=8.95\%[/tex]

Hence the experimental error will be 8.95%

Learn more on experimental error here; https://brainly.com/question/2764830

Answer:

11.5 or 11.52, depending on however many decimal places you round it to

Explanation:

the equation for mass ( using the specific heat capacity equation) is energy transferred divided by temperature change x the specific heat capacity.

so, we do 725 ÷ 32° (the temp change) x 2.03 = 11.52 or 11.5, depending on how many decimal places you round to

i would round to 2 decimal places, so the answer would be 11.52kg.

mass is measured in kg :) hope this helped.

Answer:

both spheres have a positive charge

Answer:

The formation of a gas is a clue to chemical changes. The bubbles of gas that you observed form when an antacid is dropped into water is an example of change. ... As wood burns, it turns into a pile of ashes and gases that rise into air.

Explanation:

Explanation:

these are the formula that u need to know

1. moles= concentrate × volume

2. moles = mass / mr

3. moles = volume in dm3 / 24dm^3

4. moles = Pressure in pa × Volume in m3 / 8.031 × temperature in K

hope this helps :)

Answer:

Mass of 1 mole of Aluminium = Mass of 6.02 x 10 23atoms of Aluminium =  26.98 grams.

Explanation:

1 mole of any element or molecule has 6.02 x 10 23atoms or subparts.

Hence 1 mole of aluminum will also have 6.02 x 10 23atoms. Hence, it is clear that mass of 1 mole of Aluminium will be equal to 6.02 x 10 23atoms of Aluminium.

Thus,

Mass of 1 mole of Aluminium = Mass of 6.02 x 10 23atoms of Aluminium =  26.98 grams.

Answer:

Special type of surface that repels liquid

Explanation:

Answer:

4665.97

Explanation:

Answer:

pluto is considered a dwarf planet because it did not meet the three criteria the IAU uses to define a full sized planet

Explanation:

Answer:

True

Explanation:

Cellular respiration is a metabolic pathway that allows cells to take apart food molecules and use their atoms as an energy source. This pathway takes electrons from food molecules and transfers them to oxygen, has energy transferred to ATP and arranges molecules into water, carbon dioxide and waste.

Answer: The complete nuclear symbol will be [tex]_8^{18}\textrm {O}[/tex]

Explanation:

The nuclear symbol is written as: [tex]_Z^A\textrm {X}[/tex] where Z= atomic number , A = mass number X = symbol of element

Atomic number is defined as the number of protons or number of electrons that are present in an atom.

For an electrically neutral atom,

Atomic number = Number of electrons = Number of protons = 8

Mass number is defined as the sum of number of protons and neutrons that are present in an atom.

Mass number = Number of protons + Number of neutrons  

Mass number = 8 + 10 = 18

Thus complete symbol will be [tex]_8^{18}\textrm {O}[/tex]

Answer:

Fe(NO3)3 + 3 NaOH ===》Fe(OH)3 + 3 NaNO3

Answer:

D

Explanation:

31 / 2.8 = 11.0714286 L per mole of helium

3.5 / 4 = 0.875 moles

2.8 + 0.875 = 3.675 moles

11.0714286 x 3.675 = 40.6875 L

Answer:

60

Explanation:

Answer:

its actually 83° rounding it so choose that

Explanation:

Bbbbbbbbbbbbbbbbbbbbb

Answer:

B.

Explanation:

the substance would still be pure because both of the atoms are natural

it wouldnt create something pure or new it would just combine

so it would be B

hope this helps!

~goldfishareswag/brianna

:)

Answer:

A

Explanation:

Crabs were exposed to a toxin in the water.

Answer:

Element   atom    molar mass     Total        % composition

Na               1            23                    40             57.5 %

O                 1            16                     40              40%

H                1               1                      40              2.5 %

The given compound is NaOH.

Na : number of atom= 1

Molar mass= 23 g/mol

Total mass of NaOH = 40 g/mol

% composition by mass = [tex]\frac{\text {mass of atom}}{\text {Total mass}}\times 100=\frac{23}{40}\times 100=57.5\%[/tex]

O : number of atom= 1

Molar mass= 16 g/mol

Total mass of NaOH = 40 g/mol

% composition by mass = [tex]\frac{\text {mass of atom}}{\text {Total mass}}\times 100=\frac{16}{40}\times 100=40\%[/tex]

H : number of atom= 1

Molar mass= 1 g/mol

Total mass of NaOH = 40 g/mol

% composition by mass = [tex]\frac{\text {mass of atom}}{\text {Total mass}}\times 100=\frac{1}{40}\times 100=2.5\%[/tex]

Answer:

5974 g of Na₃P

Explanation:

We determine the reaction:

2Na₃P + 3SrO  →  3Na₂O + Sr₃P₂

2 moles of sodium phosphide react to 3 moles of strontium oxide to produce 3 moles of sodium oxide and 1 mol of strontium phosphide.

We know that 1 mol of anything contains 6.02×10²³ formula units, so:

5.4×10²⁵ formula units . 1 mol/6.02×10²³ formula units = 89.7 moles

This is the amount we have, initially for SrO.

Ratio is 3:2. 3 moles of SrO react to 2 Na₃P

Then 89.7 moles of SrO may react to (89.7 . 2) /3 = 59.8 moles of Na₃P

We convert the moles to mass (mass . molecular weight)

59.8 mol . 99.9 g /mol = 5974 g

Answer:

The large relative distances between particles in a gas means that there is considerable empty space between the particles.

The assumption that particles in a gas are relatively far apart explains gas compressibility.

Compressibility is a measure of how much the volume of matter decreases under pressure.

Energy is released by a gas when it is compressed

Explanation:

The kinetic molecular theory establishes that gases are composed of molecules. These molecules of gas are far apart from each other hence there is a considerable empty space between the gas molecules. As a result of these empty spaces between gas molecules, it is possible to compress a gas.

Compressibility is defined as a measure of how much the volume of matter decreases under pressure. When a gas is compressed, work is done on the gas and energy is evolved hence the gas heats up.