Which substance cannot be broken down by chemical changes? Magnesium Hydroxide Carbon Dioxide b O Ammonia Iron
Answer:
Iron
Explanation:
The only substance that cannot be broken down by a chemical change is Iron.
Iron is an element and elements are made up of atoms. Atoms are the smallest indivisible particles that takes part in chemical reactions.
Other choices are compounds. Compounds are made by combining atoms together through the loss, gain or sharing of electrons. This interaction creates bonds between two or more species. But for substances made up of atoms alone, no bonds are formed and hence, they cannot be further broken down.Which of the following is a characteristic differentiating tropical and temperate rainforests?
a. the location
b. the types of trees
c. the average temperature
d. all of the answers are correct
Answer:
D. all of the answers are correct
Explanation:
edge 2020
Rainforests are defined by the evergreen and canopy trees. The tropical and temperate rainforests differ in the locations, type of plantation, and temperature. Thus, option d is correct.
What is a tropical and temperate rainforests?Tropical and temperate rainforests are rainforests that differ from each other based on various factors. The tropical rainforest is located at the latitude near the equator, between the Tropic of Cancer and Capricorn. They are covered with canopied trees and average warm temperature conditions.
On the other hand, the temperate rainforests are found away from the Equator near the north side of the tropics and are marked by the presence of coniferous or broadleaf trees. They have a cooler climate and two seasons.
Therefore, option d. the tropical and temperate rainforests have different temperatures, locations, and trees.
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What are the steps to
separate iron fillings, water,
leaves?
Answer:
Wrap a magnet in plastic lunch wrap and move it through the mixture of the three solids. The iron filings will stick to the magnet. The filings can be removed by unwrapping the plastic from the magnet carefully! Mix the remaining salt and sand in water and stir.
Explanation:
30 points!!! please help chem question
Answer: below -45
Explanation:
The reversible reaction, 2NO{g) ⇌ N2 (g) + O2 (g), would be classified as a __________________ reaction.
homogeneous
heterogeneous
endothermic
Your big brother has been bragging about how he can bench press 4,000 grams at the gym. Sounds impressive, but you know better. Use your skills to find how many pounds of weight he is actually pressing.
A brother is bragging about doing a bench press of 4000 grams at the gym. 4000 grams is equal to 8.818 pounds.
What is a bench press?The bench press or chest press is training or weight training to strengthen your arm and chest muscles. It is done by laying down on a bench and pushing and pulling up the bars with weight.
It is a common weight-lifting exercise in gyms. Trainers use accordingly weight on the basis of the trainee's weight and strength that is doing the bench press, and the weight is measured differently in different countries. Eight-pound is not a very big amount.
In America, weight is measured in pounds, one kg is 1000 grams and
1 gram is 0.00220462
4000 x 0.00220462
4000 grams will be 8.818 pounds.
Thus, 4000 grams is equal to 8.818 pounds.
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What is one way the lack of gravity in space affects the human body?
Please help ASAP
Answer:
Loss of muscle mass because there is no weight on the back and legs.
Explanation:
What do we mean when we say a substance is "pure"?
Answer:
A pure substance is a substance that is only made up of atoms of one element and so it has fixed melting and boiling points.
Which two particles are found in an atom's nucleus?
O A. Neutrons
O B. Electrons
O C. Protons
O D. Isotopes
Answer:
protons and neutrons so A and C
which element would be used to help support a building
C
He
Na
Fe
Which type of atom will attract electrons
Answer:
nuetrons and protons
Explanation:
Explanation:
the electron pair will be attracted more strongly to the atom that has the higher electronegativity
hope it help
if i change it by looking at it what type of change is it ?
non impact
kinetic
physical
chemical
Answer:
the answer to this is non impact
Which unit of size are the smallest organisms found on Earth?
millimeters
picometers
nanometers
micrometers
Answer:
it is nanometers the third one
Explanation:
hope this helps
The correct answer is:
(D) Micrometers
Hope this helps!
PLEASE HELP ME ASAP!!!!!! i hope you can see this!!! if you do this can you please show your work
Answer:
3.83%
Explanation:
First, find the average of the measured value. You should get 286.
291 + 287 + 295 + 281 = 1154
1154/4 = 288.5
Subtract the accepted value (300) from the average measured value (286). Take the absolute value of your answer. You should get 14.
288.5 - 300 = -11.5 = 11.5
Divide the difference from the above problem (14) by the accepted value (300). You should get 0.0467.
11.5/300 = 0.0383
Multiply by 100%.
0.0383 × 100% = 3.83%
The percent error is 3.83%.
Answer:
3.83 percent
Explanation:
Accepted Value = 300 degrees celsius
So since we are given the formula for percentage error,
we know that we have to find the average measured value since the accepted value is already provided
Average Measured Value:
Sum of all measured values / number of measured values
(291 + 287 + 295 + 281) / 4
1154 / 4
288.5 degrees celsius
Now, plugging the values in the given formula:
(average measured value - accepted value) *100 / accepted value
(288.5 - 300) * 100 / 300
-1150 / 300
-3.83 percent
Taking Absolute Value:
3.83 percent
Hence, the average value of the temperature is 3.83 percent less than the accepted value
how many atoms are in 20 grams of aluminum
Answer:
4.5 × 10²³ number of atoms Al
Explanation:
Given data:
Mass of Al = 20 g
Number of atoms of Al = ?
Solution:
The given problem will solve by using Avogadro number.
'It is the number of atoms , ions and molecules in one gram atom of element, one gram molecules of compound and one gram ions of a substance" .The number 6.022 × 10²³ is called Avogadro number.
We will calculate the number of moles of Al first:
Number of moles = mass/molar mass
Number of moles = 20 g/ 27 g/mol
Number of moles = 0.74 mol
1 mole = 6.022 × 10²³ number of atoms
0.74 mol × 6.022 × 10²³ number of atoms / 1 mol
4.5 × 10²³ number of atoms Al
The required number of atoms is [tex]4.46\times 10^{23}[/tex]
Atomic Weight:Atomic weight, also called relative atomic mass, ratio of the average mass of a chemical element’s atoms to some standard.
Given that,
Mass=[tex]20[/tex] grams
1 mole of aluminum [tex]= 27g = 6.023\times10^{23}[/tex] number of atoms 27g of aluminum contains [tex]6.023\times10^{23}[/tex] a number of atoms.
Therefore,20 grams the number of atoms is,
[tex]6.023\times10^{23}\times\frac{20}{27} =4.46\times10^{23}[/tex]
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Which list of elements from Period 2 is arranged in decreasing
ionization potential?
Answer:
It’s ionisation
Explanation:
7. A cyclist starting from rest accelerates at a rate of 6 m/s until she reaches 30 m/s. How long
does it take her to accelerate?
Answer:
Explanation:
The given values are:
a= 6m/s²
u= 0 m/s
v = 30 m/s
t= ?
The formula is :
[tex]a=\frac{v-u}{t}[/tex]
thus,
[tex]t=\frac{v-u}{a}\\t=\frac{30-0}{6}\\t= 5 seconds[/tex]
Which answer below correctly identifies the type of change and the explination for the boiling of water
Choose all the answers that apply. Which of the following energy forms are involved in a nuclear power plant?
1)heat
2)mechanical
3)electrical
4)nuclear
Answer:Three mutual conversions of energy forms occur at nuclear power plants: nuclear energy is converted into thermal energy, thermal energy is converted into mechanical energy, and mechanical energy is converted into electric energy.
Explanation:
stions and Problems What is the freezing point of Salol?
Answer:
106.7 degrees f
Explanation:
In the reaction Zn H 2SO 4→ ZNSO4 + H2, which, if any element is oxidized
Answer:
I hope this answer is correct
Explanation:
This is an oxidation-reduction (redox) reaction:
Zn0 - 2 e- → ZnII (oxidation)
2 HI + 2 e- → 2 H0 (reduction)
Zn is a reducing agent, H2SO4 is an oxidizing agent.
Reactants:
Zn
Names: Zinc source: wikidata, accessed: 2019-09-07, Zinc powder (pyrophoric) source: ICSC, accessed: 2019-09-04, Zn source: wikidata, accessed: 2019-09-07
Appearance: Grey-to-blue powder source: ICSC, accessed: 2019-09-04
H2SO4 – Sulfuric acid source: wikipedia, accessed: 2019-09-27source: wikidata, accessed: 2019-09-07source: NIOSH NPG, accessed: 2019-09-02
Other names: Oil of vitriol source: wikipedia, accessed: 2019-09-27source: wikidata, accessed: 2019-09-07source: ICSC, accessed: 2019-09-04source: NIOSH NPG, accessed: 2019-09-02, Sulfuric acid, concentrated (> 51% and < 100%) source: ICSC, accessed: 2019-09-04, H2SO4 source: wikidata, accessed: 2019-09-07
Appearance: Clear, colorless liquid source: wikipedia, accessed: 2019-09-27; Odourless colourless oily hygroscopic liquid source: ICSC, accessed: 2019-09-04; Colorless to dark-brown, oily, odorless liquid. [Note: Pure compound is a solid below 51°F. Often used in an aqueous solution.] source: NIOSH NPG, accessed: 2019-09-02
Products:
ZnSO4 – Zinc sulfate source: wikipedia, accessed: 2019-09-27source: wikidata, accessed: 2019-09-02source: ICSC, accessed: 2019-09-04
Other names: White vitriol source: wikipedia, accessed: 2019-09-27, Goslarite source: wikipedia, accessed: 2019-09-27, Zinc sulfate (1:1) source: wikidata, accessed: 2019-09-02
Appearance: White powder source: wikipedia, accessed: 2019-09-27; Colourless hygroscopic crystals source: ICSC, accessed: 2019-09-04
H2
Names: Dihydrogen source: wikidata, accessed: 2019-09-07, Hydrogen source: ICSC, accessed: 2019-09-04source: wikidata, accessed: 2019-09-07, H2 source: wikidata, accessed: 2019-09-07
Mintu wants to increase the heat transfer between a metal iron and another piece of metal he wants to shape. He decides to increase the time the two metals are in contact, use a larger metal iron, and use a new metal material with a higher specific heat.
Where is Mintu's error?
Answer:
Mintu should chosen a material with a lower specific heat
Explanation:
I got the answer right on the test trust me it is correct
Enter the cycle number, n, in the x column and the number of radioactive atoms in the y column. When you finish, resize the window.
Answer:
at first click done,
A: exponential
then, i just put 0.5, and somewhat close.
Explanation:
edge 2021!!!
How many grams of chloride are there in 256 g of magnesium chloride?
Given :
Mass of given magnesium chloride, m = 256 g.
To Find :
How many grams of chloride are there in 256 g of magnesium chloride.
Solution :
Molecular formula of magnesium chloride is [tex]MgCl_2[/tex].
Molecular formula of [tex]MgCl_2[/tex] is, M = 95.211 g/mol .
Mass of chlorine in 1 mol of [tex]MgCl_2[/tex] is , m = 35.5 × 2 = 71 g.
So, amount of chlorine in 256 gram [tex]MgCl_2[/tex] :
[tex]m =\dfrac{71\times 256}{95.211}\\\\m = 190.90\ g[/tex]
Hence, this is the required solution.
Which of the following is an example of physical change?
Answer:
The glass cup falling from the counter
Explanation:
the glass isn't changing in any chemical way. it's still made of the same material, just broken apart.
12 PTS!! WILL GIVE BRAINLIEST!! DUE TODAY!!
The experiment is increasing and decreasing the amount of predators, pollution, and food to see how the cricket frogs will react.
Test variable (independent variable):
Outcome variable (dependent variable):
Control group:
Answer:
Test variable (independent variable): Predators, Pollution, Food.Outcome variable (dependent variable): Cricket Frogs.Control group: Beginning Frog Count
Explanation:
If pollution isincreased, then the cricket frog population will (stay the same) over the span offive years.If the amount of food available isincreased, then the cricket frog population will (increase) overthe span of five years.Procedure:The procedures are listed in your virtual lab. You do not need to repeat them here. Please be sureto identify the test variable (independent variable), outcome variable (dependent variable), andcontrol group for this experiment.
what are they waiting? or what are their waiting?
please correct me if I'm wrong
Kinds of matter with label and example
Answer:
Liquid: water
Solid: Rocks
Gas: Air
Explanation:
HELP!!!!
An unknown gas effuses at a rate of 2.0 times the rate of CL2. What is the molar mass of the unknown gas?
The molar mass of the unknown gas is 17.75 g/mol
From Graham's law of diffusion, we understood that the rate of diffusion of a gas is inversely proportional to the square root of the molar mass of the gas as shown below:R ∝ [tex]\frac{1}{\sqrt{M}}[/tex]
Expanding further, we have
[tex]\frac{R_{1} }{R_{2} } = \sqrt{\frac{M_{2}}{M_{1}} }[/tex]
Where
R₁ and R₂ are the rate of diffusion of the individual gas
M₁ and M₂ are the molar masses of the individual gas.
With the above information in mind, we can obtain the molar mass of the unknown gas as follow:
Let R₁ be the rate of the unknown gas
Let R₂ be rate of Cl₂ gas
Let M₁ be the molar mass of the unknown gas
Let M₂ be the molar mass of the Cl₂ gas
From the question given above, we were obtained the following:
Rate of the unknown gas = 2 times the rate of Cl₂ i.e
R₁ = 2R₂Molar mass of Cl₂ (M₂) = 2 × 35.5 = 71 g/mol
Molar mass of the unknown gas (M₁) =?[tex]\frac{R_{1} }{R_{2} } = \sqrt{\frac{M_{2}}{M_{1}} }\\\\\\\frac{2R_{2}}{R_{2} } = \sqrt{\frac{7 1}{M_{1}} }\\\\2 = \sqrt{\frac{7 1}{M_{1}} }[/tex]
Square both sides[tex]2^{2} = \frac{71}{M_{1}} \\\\4 = \frac{71}{M_{1}}[/tex]
Cross multiply4 × M₁ = 71
Divide both side by 4[tex]M_{1} = \frac{71}{4}[/tex]
M₁ = 17.75 g/molTherefore, the molar mass of the unknown gas is 17.75 g/mol
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*
2. Which of the following is an example of mass?
O A. 7 cm3 of air in a balloon
B. 1 mL of water in a test tube
O C. 4 centimeter piece of string
D. 8 kilograms of bananas