Answer:
test tube
Explanation:
test tube is a very small thin glass in the science lab and it's contain small amount of chemicals as they react
define SI unit system
Answer:
The SI base units are the standard units of measurement defined by the International System of Units (SI) for the seven base quantities of what is now known as the International System of Quantities: they are notably a basic set from which all other SI units can be derived.
describe an activity to separate the mixture of sand and water
Answer:
Sedimentation and decantation
Explanation:
Sedimentation and decantation: Mixture is kept undisturbed for some time. After some time, sand being heavier and insoluble in water, settles down at the bottom of container. Now, water is poured into another container to separate it from sand.
Answer:
evaporation or destillation
Explanation:
When sand is added to water it either hangs in the water or forms a layer at the bottom of the container. Sand therefore does not dissolve in water and is insoluble. It is easy to separate sand and water by filtering the mixture. Salt can be separated from a solution through evaporation.
7. In a remote area of Columbia, kids have to travel to school on a zip-line!
Would school attendance increase if all kids has to get to school on a fun
zip line?
Make a hyphotesis
Help plz!!!
Answer:
yes
Explanation:
Kids like fun things, and school is not fun , so if kids got to go to school on a zipline, attendance would be through the roof!
Magnesium and Hydrochloric acid (HCl) react to form magnesium chloride (MgCl2) and hydrogen gas. If you started with 65.8 g of magnesium and 45.7 g of hydrochloric acid. What is the limiting reactant? Ensure you post calculations to prove your answer. (3 marks)
Answer:
Cl
Explanation:
n for Mg=m:Mm
=65.8:24
=2.74mol
n for Cl=m:Mm
=45.7:70
=0.65mol
According to the number of moles we can say that the limiting reagent is Cl as it has few moles.
Limiting agents are the reactant that determines the amount of the product in a reaction. In the reaction between magnesium and hydrochloric acid, the limiting reagent is HCl.
What is a limiting reagent?A limiting reagent is a substance that restricts or determines the amount of product formation in a reaction. They are the reactants with less number of moles and get consumed in the reaction before the other reactant.
The reaction between magnesium and hydrochloric acid is given by,
Mg(s) + 2HCl(aq) → MgCl₂(aq) + H2(g)
Here, 1 mole of Mg and 2 moles of HCl are required to produce 1 mole of magnesium chloride.
The moles of Mg,
= 65.8 g ÷ 24.305
= 2.707 mol
And, moles of HCl
= 45.7 g ÷ 36.458
= 1.253 mol
The stoichiometric ratio Mg : HCl = 1:2
Hence, Mg = 2.707 ÷ 1 = 2.707 and HCl = 1.253 ÷ 2 = 0.6265
Therefore, HCl is the limiting reagent.
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What is the mass of the block of iron that has 10 cm 5 cm and 2 centimeters
Answer:
787.4g
Explanation:
The dimensions of the iron block is given as follows;
L = 10cm, B = 5cm, H = 2cm
Volume = L × B × H
Volume = 10 × 5 × 2
Volume = 100cm³
Density of iron metal = 7.874 g/cm³
Using the formula;
Density = mass/volume
Mass = density × volume
Mass = 7.874 × 100
Mass of iron = 787.4g
In an electrochemical cell, equilibrium is the point at which:
A. None of these
B. both electrodes have an equal number of electrons.
C. ion concentrations are no longer changing and the voltage is 0.
D. Equilibrium cannot be reached in a voltaic cell because electrons only flow in one direction.
Answer:
C. ion concentrations are no longer changing and the voltage is 0.
Explanation:
Electrochemical cells are a device that generates current from redox reactions. In the cell, the equilibrium is reached when the voltage drops to 0. Thus, option C is correct.
What is an electrochemical cell?An electrochemical cell is a voltaic device that uses chemical energy to generate electrical energy and vice versa. It is of two types electrolytic and galvanic cells depending on the energy it produces.
The electrochemical cell comprises two electrodes namely an anode and cathode, a salt bridge or the porous barrier, and an external connection.
The connection shows the voltage that indicates the equilibrium. When the current flow stops and the voltage reaches zero, the electrochemical cell is said to be in equilibrium.
Therefore, no change in the ionic concentrations and zero voltage indicates equilibrium.
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what volume of 2.0 m hcl contains 0.50 mol hcl?
Answer:
the volume of the acid is 250 mL.
Explanation:
Given;
number of moles of the Hcl acid, n = 0.5 mol
concentration of the acid, C = 2.0 M = 2 mol/L
let the volume of the acid = V
The volume of the acid is calculated by applying the following equation;
n = CV
V = n/C
[tex]V= \frac{0.5 \ mol}{2 \ mol/L}[/tex]
V = 0.25 L
V = 250 mL
Therefore, the volume of the acid is 250 mL.
A sample of oxygen gas occupies a volume of 160 liters at 364 K. What will be the volume of the gas when the temperature drops to 273 K?
210 L
120 L
62 L
470 L
Answer:
62L
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tysm.
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hope it help
Câu 6: Cho 4,2 gam este đơn chức no E tác dụng hết với dung dịch KOH ta thu được 4,76
gam muối natri. Vậy công thức cấu tạo của E có thể là:
Silica (also known as silicon dioxide) reacts with hydrofluoric acid to produce silicon tetrafluoride and water vapor.
a) Write the balanced chemical equation for the reaction
b) 12.5 g of silicon dioxide is reacted with a 24.6 g of hydrofluoric acid. What is the theoretical yield of water vapor?
c) If the actual yield of water vapor is 2.50 g, what is the percentage yield of the reaction?
The problem is solved by balancing the reaction equation as shown below. The stoichiometry of the reaction is now applied in solving the question.
The balanced reaction equation is:
SiO2 + 6HF → H2[SiF6] + 2H2O
Using stoichiometry
The amount of silicon dioxide reacted = 12.5 g/60.08 g/mol = 0.21 mole
1 mole SiO2 yields 2 moles of H2O
0.21 mole of SiO2 yields 0.21 * 2/1 = 0.42 moles of H2O
The amount of HF reacted = 24.6 g/20.01 g/mol = 1.23 moles of HF
6 moles of HF yield 2 mole of H2O
1.23 moles of HF yields 2 * 1.23/6 = 0.41 moles of H2O
Hence HF is the limiting reactant.
Theoretical yield of H2O = 0.41 moles of H2O * 18 g/mol = 7.38 g
The percentage yield of the water is = actual yield/theoretical yield * 100
Hence;
% yield = 2.50 g/7.38 g * 100 = 33.9%
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A student wants to separate a mixture of salt and water in a laboratory (a) Describe how the student can obtain both salt and water from the salt solution
Answer:
okay so basically what you are being tested is if you know the difference between simple and fractional distillation and okay you can evaporate the mixture but you won't obtain water so you will use simple distillation to obtain both salt and water
which best describes nuclear energy?
A the energy that matter has due to the vibrations of its particles
B the energy an object has due to its chemical bonds
C the energy generated by a flow of electrons
D the energy stored inside the center of an atom
Answer:
The correct answer is - D. the energy stored inside the center of an atom.
Explanation:
Each atom has a small center in it called the nucleus and the energy that holds the nucleus or center of the atom together in the atom is known as nuclear energy.
It is the energy that is stored in the center of the atom and normally does not come out, however, in some radioactive atoms the sends some part of the energy as radiation.
Thus, the correct answer is - D. the energy stored inside the center of an atom.
what is plasma in chemistry
Explanation:
Plasma is an ionized gas, a distinct fourth state of matter. “Ionized” means that at least one electron is not bound to an atom or molecule, converting the atoms or molecules into positively charged ions.but plasma is present in human body too in a liquid form.
hope this helps you
have a nice day
9. a) Name salt that can be prepared by precipitation
I think its the substances that sublimes
Convert 15,000 seconds into minutes
Answer:
250 minutes
Explanation:
60 seconds = 1 minute
15000 secods = 15000 / 60
1500 secons = 250 minutes
PLS HELP WILL GIVE BRAINLIEST
it is a simple chemistry question
i thought F has 9 electrons, so why does this structure show 8 electrons.
Answer:
The IUPAC structure only shows bond pairs and lone pairs. In the flouromethane structure above, there is only one bond pair and three lone pairs of electrons. Therefore there is one electron remaining, but since it doesn't not make up a pair, it is ignored in the structure but theoretically it is present.
[tex].[/tex]
Answer:
therefore there is one electron remaining , but since it doesn't make up a pair . It is ignored in the structure but theoretically it is present .
Aluminum hydroxide containing medicine is used for gastric why
Answer:
Aluminum Hydroxide, Magnesium Hydroxide are antacids used together to relieve heartburn, acid indigestion, and upset stomach. They may be used to treat these symptoms in patients with peptic ulcer, gastritis, esophagitis, hiatal hernia, or too much acid in the stomach (gastric hyperacidity).
Answer:
wow it's a very nice question
For the metal Mg 109.5g solution HCl 10%. a) Case of metal b) Its properties
Answer:
Explanation:
mg +2hcl=mgcl2 +h2
mhcl=10.95g
nhcl==0.3
nmg=1/2nhcl=0.15
mMg=3.6g
m mgcl2=14.25
what occurs when the vapor pressure of a lquid is equal to the external atmospheric pressure
Answer:
The change from a liquid phase to a gaseous phase occurs when the vapor pressure of the liquid is equal to the atmospheric pressure exerted on the liquid.
Explanation:
Boiling is a physical change and molecules are not chemically altered during the process.
If an atom has three shell and number of valence electrons are two. Is this element metal
or non-metal and why? Name the element and it’s valency.
Answer:
Metal
Element: Calcium
Valency: 2
Explanation:
To find the element, let's use the periodic table. (Look below)
We already went past 3 shells, just need the 2 electrons after it.
Just skip to the 4th row and count 2 to the right
We end up at Calcium.
Calcium is a metal and we're also on the alkaline earth metals column.
Calcium will need to lose 2 electrons to reach stability, so the valency is 2.
The law of conservation of energy states that A: energy is always created and destroyed B: energy cannot be created or destroyed C: energy is unable to change forms D: energy should be saved as often as possible
Answer:
B
Explanation:
This is the First Law of Thermodynamics which states that energy cannot be created or destroyed.
Arrange the steps in order to describe how photons and carbon dioxide (CO2) contribute to the warming of Earth.
CO2 in the atmosphere absorbs infrared
photons.
CO2 in the atmosphere emits infrared photons back toward Earth.
Photons from the Sun strike Earth and become infrared photons.
Earth radiates infrared photons into the atmosphere
The Sun radiates sunlight (visible)
photons
The Sun radiates sunlight (visible) photons
Photons from the Sun strike Earth and become infrared photons.
Earth radiates infrared photons into the atmosphere
CO2 in the atmosphere absorbs infrared photons.
CO2 in the atmosphere emits infrared photons back toward Earth.
Certain gases are known to contribute towards global warming. Such gases are called greenhouse gases. The infrared rays from the sun are absorbed by these gases as they are re-emitted from the earth and re-emitted.
The sun radiates photons to the earth which is re-radiated into outerspace from the earth's surface. CO2 and other greenhouse gases absorbs these gases and re-emit them to the earth thereby causing a gradually rise in the temperature of the earth called global warming.
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Câu 1: Trong các dung dịch sau, dung dịch nào làm quỳ tím đổi màu xanh?
A. HCl B. H2SO4 C. NaOH D. NaCl
Câu 2: Bazơ nào dưới đây là bazơ không tan?
A. KOH B. NaOH C. Cu(OH)2 D. Ca(OH)2
Câu 3: Trong các chất sau đây, chất nào không phải là muối?
A. HCl B. KCl
C. NaOH
C. Cu (OH)
A. HCl
Im sorry if its difficult to read
we dont talk about how I messed up my first question and jad to make another one because im slow
Answer:
A ball is thrown straight up from a rooftop 320 feet high. The formula below describes the ball's height above the ground, h, in feet, t seconds after it was thrown. The ball misses the rooftop on its way down and eventually strikes the ground. How long will it take for the ball to hit the ground? Use this information to provide tick marks with appropriate numbers along the horizontal axis in the figure shown.
h=-16t^2+16t+320
Which statement best describes redox behavior in an electrochemical cell?
Electrons are produced at the copper rod.
Electrons flow from cathode to anode.
Reduction occurs at the zinc electrolyte.
Charges are balanced during redox.
Answer:
The last one
Explanation:
Charges are balanced in a redox reaction
PLZ HELP what is a sign that a chemical change has happened
Answer:
Some signs of a chemical change are a change in color and the formation of bubbles. The five conditions of chemical change: color change, formation of a precipitate, formation of a gas, odor change, temperature change.
A phase change from a solid to a gas is called:
Answer:
sublimation
Explanation:
H3C6H507 + H2O + H3O+ + H2C6H507
acid
base
Explanation:
an acid will give away a proton and become a conjugate base.
A base will accept a proton and become a conjugate acid.
Think of a real life simple problem and apply scientific method to solve the problem given to the guide questions.
Scientific Approach is to identify a problem and finding solution to the problem. There are various steps in scientific approach to solve a problem,
Identify the problem
Analyze the impact
Find available solution
Evaluate different alternative solutions
Choose the best alternative
Apply the solution to the problem
Measure the results
Lets say there is a fire at some place.
There are various solution available, the fire can be slowed down by water, using fire extinguisher or sand.
The best alternative is to use fire extinguisher.
The fire is vanished after the use of fire extinguisher.
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Organisms do not adapt as a result of competition for resources.
Answer:
The given statement is False.
The organisms adapt as a result of competition for resources. Different places have different organisms suited for that particular places.
The animals living at a particular place compete for the resources available and the nature selects the organism that has won the competition for resources.
The organisms are evolved as a result of competition for resources
Answer:
I just wanted to say the other person is totally right.
this statement is false.
