Al wonders if adding salt to water will affect how long it takes the water to
freeze. Al thinks that salt water will freeze more quickly than fresh water.
He decides to check his hypothesis by conducting an experiment. Al takes
two ice trays and fills one with distilled water and the other with distilled
water that has two tablespoons of salt added. He makes sure he puts
exactly the same amount of water in each ice tray. Al takes the trays and
puts them side by side in the freezer. Al checks the ice trays every 10
minutes to see if the water in each tray has begun to freeze. Al finds that
after 20 minutes the water in the ice tray without the salt has started to
form ice, while the ice tray with the salt water is still completely liquid.
Ku

While picking up a buret, an unknown solution left by a previous solution drips onto your hand - Gloves

While pulling an empty beaker off the shelf at the beginning of lab, it slips out of your hand onto the floor - Closed-toe shoes

While checking on a stirring solution, the solution splashes up towards your face - Goggles

While transferring a solution from a flask to a beaker, the solution accidentally spills down the front of the lab bench - Lab coat

Explanation:

So, according to the question. the matches will be:

While picking up a buret, an unknown solution left by a previous solution drips onto your hand - Gloves

While pulling an empty beaker off the shelf at the beginning of lab, it slips out of your hand onto the floor - Closed-toe shoes

While checking on a stirring solution, the solution splashes up towards your face - Goggles

While transferring a solution from a flask to a beaker, the solution accidentally spills down the front of the lab bench - Lab coat

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Answer:

The Cavendish experiment, performed in 1797–1798 by English scientist Henry Cavendish, was the first experiment to measure the force of gravity between masses in the laboratory and the first to yield accurate values for the gravitational constant

Explanation:

I think that's correct

Answer:

0.017g/mol

Explanation:

according to the mole concept to calculate the number of moles of a substance you use the formula

number of moles= mass/molecular mass

=4.5g/254g/mole

=0.017moles

I hope this helps and sorry if it's wrong

Answer:

E

Explanation:

kinetic energy of linear motion

[tex]k.e = \frac{1}{2} m {v}^{2} [/tex]

kinetic energy, K.e= 100joules

mass, m = 2kg

velocity, v =?

substituting the values into the formula :

[tex]100joules = \frac{1}{2} \times 2kg \times {v}^{2} [/tex]

[tex] {v }^{2} = 100[/tex]

[tex]v = \sqrt{100 } [/tex]

[tex]v = 10m { \sec }^{ - 1} [/tex]

Answer:

A

Explanation:

The instrument in which the washer works as a valve is  A ; syringe

Each instrument listed have a washer and a valve, but of all the instruments listed above the instrument that its washer works also as a valve is the syringe.

A syringe is composed of a thin tube and a thinner hollow needle attached to the end of the thin tube. the needle is used and take in liquids and also expel liquids from the syringe ( i.e. washer and valve )

hence the instrument that its washer also functions as a valve is the syringe.

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Answer:

since there are no lone pairs on the central atom, this would be a trigonal planar molecule. It's polar because the shape of it does not cancel its polarity (you can think of it as not having a balanced electronegativity pull, since the nitrogen is pulling on one side, and the oxygens are pulling on the other. It would be nonpolar if the there were 3 Oxygens).

Sorry this take a little bit long. I was a little confused by the odd valence number

Answer:

b is the answr

Explanation:

The correct answer is Option (B) Enrichment of Uranium-235 is done.

Hence Option (B) is correct because enrichment of uranium-235 is achieved by the process of conversion So , It does not facilitate containment

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#SPJ2

1. Cl2 + H2O → HOCl + HCl

2. Tooth decay starts when when the pH of the mouth is lower than 5.5. Tooth enamel is made up of calcium phosphate and it is one of the hardest substances of the body. But it is corroded when the pH is less than 5.5. The bacteria of our mouth produce acids by degradation of sugar and food particles remaining in our mouth after eating food.

3. Fluorine salts are added in toothpaste to protect our teeth from tooth decay. Fluorine salts are mildly basic, so they neutrelise the acid in our mouth that leads to tooth decay.

4. Tincture of iodine is iodine, pottasium iodide and sodium iodide dissolved in ethanol. Iodine acts in an antiseptic manner by destroying microbial proteins and DNA.

5. Tincture of iodine is clear and reddish brown liquid.

Answer:

i think A.

Explanation:

bc B. makes the molecules hight temp = move faster = more collisions = higher rate, C. it's use is to make reactions rates increase, D. somthung abt more surface area and easier collisions

Answer: first of all an ionic bonds is the electrostatic force of attraction between opposite ions and and covalent bonds is the bond between different elements mostly non metals or the sharing of electrons between elements which are mostly non metals.

Explanation:  metals and non metals react to form ionic compounds

and non metals react to form covalent bonds

HOW TO DIFFERENTIATE

ionic solids the particles are charged and the forces between them are strong

covalent solids the particles are not charged and the forces between them are weak

now i would differentiate using their  properties

ionic bonds  / compounds

have high melting point

have low melting point

They are soluble in water

and they conduct electricity even when melted or dissolved in water

covalent bonds /compounds

they have low melting point

they have low melting point

They are insoluble

they do not conduct electricity

HOPE THIS HELPS!!!

Answer:

The answer is "Auger".

Explanation:

The Auger effect is an effect size when the vacancy of even an atom throughout the inner shell was complemented by the release of even an electron from the same atom. Whenever a central electron is lost, a higher energy level electron can drop into the void and release energy, which can be the result.

Answer:

1.Physical change

2. Chemical change

3. Heat

4.photosynthesis

5. composition

Answer:

0.68

Explanation:

This is because the formula for finding density is mass/volume. Therefore the equation becomes 5.6/8.2 giving you 0.68

Answer:

15g

Explanation:

First, you need to correct the answer to the previous question. The percentage by mass of Mg in MgO =

Mg = 24.3 amu

O = 16.0 amu

The total mass of MgO = 40.3 amu

To calculate the percent composition of Mg:

% = 24.3/40.3 x 100

% = 60

To calculate the mass of Mg needed to make 25g of MgO:

x/25g = 60%/100%

100x = (25)(60)

100x = 1500

x = 15g

Answer:

What atoms are present in carbon tetrachloride?

There is 1 carbon, and 4 chlorine atoms (or chloride ions if you want to get technical). Tetra means 4 in Greek.

hope that helps❤

Answer:

there are no calcium atoms of n carbon tetrachloride

both electronegativity and ionization energy increase from bottom to top and from left to right

on the periodic table.

Answer:

132.17amu

Explanation:

(14.01+1.01 multiplied by 4)=18.05×2=36.1

36.1+32.07= 68.17

16.00×4=64

68.17+64=132.17

Answer:

132.17 amu

Explanation:

just took the test. got 100

Answer:

Pottasium

Explanation:

because it is the nineteenth element

Answer:

The answer is B. Potassium.

Explanation: Potassium has 19 electrons that are organized like the image if you count the electrons on each obital. This answer is correct on edge 2020. Hope this helps!

Answer:

A water molecule is composed of two hydrogen atom and one oxygen atom but you can't simply take two hydrogen atom stick them onto an oxygen atom

Answer:

Divide the mass of the solute by the total volume of the solution. Write out the equation C = m/V, where m is the mass of the solute and V is the total volume of the solution. Plug in the values you found for the mass and volume, and divide them to find the concentration of your solution.

Answer:

29.41% of Calcium and 47.04% of Oxygen

Explanation:

The percent composition of an atom in a molecule is defined as 100 times the ratio between the mass of the atom and the mass of the molecule.

The mass of the molecule of the problem (Ore) is 46.28g. That means the percent composition of Calcium is:

13.61g / 46.28g * 100 = 29.41% of Calcium

And percent composition of Oxygen is:

21.77g / 46.28g * 100 = 47.04% of Oxygen

Answer:

Triads were groups of 3 elements with similar chemical and physical properties. Beryllium, magnesium, and calcium are all earth alkalis found in the earth

Explanation:

Answer:

When an atom has an equal number of electrons and protons, it has an equal number of negative electric charges (the electrons) and positive electric charges (the protons). The total electric charge of the atom is therefore zero and the atom is said to be neutral.

I HOPE THIS HELPS !!!!!!!!!!!

Answer:

A). 2.1 × [tex]10^{-2}[/tex]

Explanation:

Given reaction,

2[tex]HF[/tex] (g) ⇄ [tex]H_{2}[/tex] (g) + [tex]F_{2}[/tex] (g)

The concentrations are as following;

[tex]HF[/tex] = 5.82 × [tex]10^{-2}[/tex] M

[tex]H_{2}[/tex] = 8.4 × [tex]10^{-3}[/tex] M

[tex]F_{2}[/tex] = 8.4 × [tex]10^{-3}[/tex] M

So,

[tex]K_{eq}[/tex] = [([tex]H_{2}[/tex] ) × ([tex]F_{2}[/tex])] ÷ [[tex]HF[/tex]]^2

Now,

We can determine the value of [tex]K_{eq}[/tex] by substituting the values in above formula:

[tex]K_{eq}[/tex] = [ (8.4 × [tex]10^{-3}[/tex] M) × (8.4 × [tex]10^{-3}[/tex] M)] ÷ [(5.82 × [tex]10^{-2}[/tex])^2

= 2.08 * [tex]10^{-2}[/tex]

=  2.1 × [tex]10^{-2}[/tex]

∵ [tex]K_{eq}[/tex] = 2.1 × [tex]10^{-2}[/tex]

Thus, option A is the correct answer.

Answer:

could occur at any temperature.

Explanation:

The spontaneity of a reaction is what determines whether the reaction will occur or not. A spontaneous reaction occurs easily.

The spontaneity of a reaction is predicted by the sign of ∆G.

When ∆G is positive, the reaction is not spontaneous. When ∆G is negative, the reaction is spontaneous.

Note that;

∆G= ∆H - T∆S

Where;

∆H = Change in enthalpy

∆S = Change in entropy

T= temperature

If ∆H is unfavourable and ∆S is favourable, the reaction can proceed at all temperatures because ∆G will always be negative.

It should be noted that a process that is unfavorable as regards to enthalpy, but favorable with respect to entropy could occur at any temperature.

Enthalpy(∆H) serves as amount of internal energy that a compound has, entropy( ∆S)  on the other hand serves as intrinsic disorder within the system.

However, spontaneity of a reaction determines likely hood of occurrence of a reaction, when the process is spontaneous, it makes the reaction to occurs easily.

We can conclude that whenever enthalpy is unfavourable and entropy of a system is favourable, then the spontaneity will be negative and the reaction will occur at any temperature.

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Explanation:

The given chemical equation is:

[tex]2A + 4B -> 2C + 2D[/tex]

The rate of the reaction is 0.0352 M/s.

During the course of the reaction, the rate of reactants decreases, and the rate of products increases.

The rate of disappearance of B is shown below:

[tex]rate=-\frac{1}{4} \frac{d[B]}{dt}[/tex]

So, rate of change of B is :

[tex]rate of change of B =- rate * 4\\=-0.0352 M/s * 4\\=-0.1408M/s\\\\=-0.141M/s[/tex]

Option C.

In the given reaction, rate of change of reactant B is equal to -0.141 M/s.

Rate of any chemical reaction defines the speed of the completion of that reaction.

In the question given reaction is:

2A + 4B ----> 2C + 2D

Rate of reaction = 0.0352 M/s.

Rate of the reaction with respect to the reactant B is written as:

Rate = [tex]${\rm{ - }}\frac{{\rm{1}}}{{\rm{4}}}\frac{{\left[ {{\rm{dB}}} \right]}}{{{\rm{dT}}}}$[/tex], where negative sign shows the disappearance of reactant B.

Rate of change of B i.e. [tex]$\frac{{{\rm{dB}}}}{{{\rm{dT}}}}$[/tex] =  4 × (-rate)

[tex]$\frac{{{\rm{dB}}}}{{{\rm{dT}}}}$[/tex] =  4 × (-0.0352) = -0.1408 = -0.141 M/s

Hence, -0.141 M/s is the rate of change of B.

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Answer:

The law of reciprocal proportions states that if two elements react individually with a given weight of a third element, the ratio of the masses with which they combine with the third element are either the same or a simple multiple of the ratio of the masses with which they combine with each other

The compounds formed includes;

1) Nitric oxide, NO

Nitrogen = 46.66% × 30.01 = 14

Oxygen = 53.34% × 30.01 = 16

2) Water, H₂O

Hydrogen = 11.21% × 18.01528 = 2

Oxygen = 88.79% × 18.01528 ≈ 16

3) Ammonia, NH₃

Hydrogen = 17.78% × 17.031 ≈ 3

Nitrogen = 82.22% × 17.031 ≈ 14

The ratio of nitrogen to oxygen in nitric oxide = 14:16 = 7:8

The ratio of nitrogen to hydrogen in ammonia = 14:3

The ratio in which hydrogen and oxygen combine with nitrogen = 3/16

The ratio of hydrogen and oxygen combine with each other in water = 2/16

Therefore, the ratio with which hydrogen and oxygen combine with nitrogen, is (2/3) times the ratio with which they combine with each other, which verifies the law of reciprocal proportions

Explanation: