Need the answer ASAP!!!

Select the correct answer.
A student puts a glass of water in the freezer. Later, he notices ice forming on the surface of the water. Which property of water best explains
why ice forms on its surface?
OA
Ice has more surface tension than liquid water,
OB.
Ice is less dense than liquid water.
OC.
Ice has a lower freezing point than liquid water.
OD
Ice is more cohesive than liquid water.
O E.
Ice can dissolve more oxygen than liquid water.

Answer:

Lead can harm production of blood cells and the absorption of calcium needed for strong bones and teeth, muscle movements, and the work of nerves and blood vessels. High lead levels can cause brain and kidney damage.

thanks

Once lead enters the body, it is distributed to organs such as the brain, kidneys, liver and bones. The body stores lead in the teeth and bones where it accumulates over time. Lead stored in bone may be remobilized into the blood during pregnancy, thus exposing the fetus.

The equation is balanced.

The number of P atoms in the reactant side is 4 and the number of P atoms in the product side is also 4.

The number of O atoms in the reactant side is 16 and the number of O atoms in the product side is also 16.

The number of H atoms in the reactant side is 12 and the number of H atoms in the product side is also 12.

These results are in accordance with the law of conservation of mass.

#ILoveChemistry

Answer:

Nitrogen

Explanation:

According to the Periodic Table, the atom with a mass is 16 but the Atomic number is 7 for Nitrogen. That means that Nitrogen is an isotope.

Answer:

B

Explanation:

When the amount of gas in a container is increased, the volume increases. Lussac's law states that the pressure of a given amount of gas held at constant volume is directly proportional to the Kelvin temperature.

Answer:

Due to increase in carbondioxide gas.

Explanation:

The buffering action of these chemical reactions is limited by the present day rate of change for atmospheric carbondioxide concentration because the the rate of atmospheric carbondioxide rises as compared to ancient atmospheric carbondioxide gas. Due to increase of human activities, the concentration of carbondioxide gas increases in the atmosphere which limits the buffering action of these chemical reactions so we can say that carbondioxide gas is responsible for its limited action.

Answer:

see your answer in pic

Explanation:

There can be emissions of radiations like gamma radiation. There can be emission of particles too like alpha particle. Therefore, the nuclear equation for the beta decay of Promethium-165 is

¹⁶⁵Pm[tex]\rightarrow[/tex]⁰e₋₁  +  ₆₂Sm¹⁶⁵

Nuclear decay is process in which the radioactive element releases particles or radiations. Alpha particles is ⁴₂He. Alpha particle is nothing but helium particle. The kinetics that is related to nuclear decay is of first order.

The nuclear equation for the beta decay of Promethium-165 is

¹⁶⁵Pm[tex]\rightarrow[/tex]⁰e₋₁  +  ₆₂Sm¹⁶⁵

Beta decay of  Promethium-165 is the emission of electron particle from the given isotope. the product is Samarium  ₆₂Sm¹⁶⁵.

Therefore, the nuclear equation for the beta decay of Promethium-165 is

¹⁶⁵Pm[tex]\rightarrow[/tex]⁰e₋₁  +  ₆₂Sm¹⁶⁵

To know more about nuclear decay, here:

https://brainly.com/question/21114779

#SPJ2

Answer:

9

Explanation:

I took the same test :)

The stoichiometry is important in chemistry which helps us to use the balanced equation to calculate the amount of reactants and products. Here the moles of hydrogen needed is 9. The correct option is B.

The quantitative study of the reactants and products involved in a chemical reaction is known as the chemical stoichiometry. The stoichiometric coefficients can be fractions including the whole numbers.  It helps to establish the mole ratio.

The stoichiometric coefficient is basically the number which is present in front of the atoms, molecules or ions. The stoichiometric calculations are also used in gravimetry and volumetry.

Here the balanced equation for the reaction is:

N₂ + 3H₂ → 2NH₃

Number of moles of H₂ = 3 mol N₂× 3 mol H₂  / 1 mol N₂ = 9 mol H₂

So the number of moles of H₂ is 9.

Thus the correct option is B.

To know more about stoichiometry, visit;

https://brainly.com/question/29775083

#SPJ7

Answer: hello your question has some missing details attached below is the missing details

answer : 25.5%  ( B )

Explanation:

Determine percentage yield

molar mass = 35 g/mol

mass of Li₃N(s) = 70 g

product  LiH(s) = 8.0 g ( actual yield )

theoretical yield ( LiH ) =  4 * 7.95  = 31.8 g

percentage yield = actual yield * 100 / theoretical yield

                            = 8 * 100/31.8

                            = 25.5%

Explanation:

dylalove464

06/11/2020

Hello,

In this case, we first compute the moles of oxygen in 0.654 g and 1.35 g by using its molar mass (32 g/mol):

Then, by using the ideal gas equation at the both states, given the same both temperature and volume:

We compute the volume at the second moles:

Best regards.

Answer:

3.41

Explanation:

:)

Answer: 1) 400N

2)1.6

Explanation:

1) 5cm = 100N of force

so

20cm=400n

2) 0.4 X 4 = 1.6

Answer:

A

Explanation:

balance the trades and improving them

Answer:

A:try to improve it's balance of trade

Explanation:

Answer: Out of the given options bonds connecting atoms in reactants break, and bonds connecting atoms in products form are the changes which takes place when a chemical change occurs.

Explanation:

A change that leads to the change in chemical composition of a substance is called a chemical change.

For example, [tex]2NH_{3} \rightarrow N_{2} + 3H_{2}[/tex]

Here, bond between the reactant atoms nitrogen and hydrogen is broken down.

On the other hand, bond connecting the products that is [tex]N_{2}[/tex] and [tex]H_{2}[/tex] is formed.

Thus,, we can conclude that out of the given options bonds connecting atoms in reactants break, and bonds connecting atoms in products form are the changes which takes place when a chemical change occurs.

Explanation:

Melting is defined as the physical process where a solid state of a substance converts into its liquid state. No change of chemical composition takes place, just the physical state of water is changing.

[tex]\text{Solid}\rightleftharpoons \text{Liquid}[/tex]

There are given carboxylic acids. The melting point of these acids increases to its second group member which is ethanoic acid due to prevalent hydrogen bonding. To break this bonding, a high amount of heat needs to be applied.

But as we move forward, the melting point decreases sharply as an increase in the number of carbon atoms decreases the hydrogen bonding.

Melting point of Formic Acid = [tex]8.3^oC[/tex]

Melting point of Acetic Acid = [tex]16.6^oC[/tex]

Melting point of Propionic Acid = [tex]-21^oC[/tex]

Answer:

1.28 g

Explanation:

Mass of anhydrous compound/molar mass of anhydrous compound = mass of hydrated compound/ molar mass of hydrated compound

Mass of anhydrous compound = ?

Mass of hydrated compound = 2g

Molar mass of anhydrous compound= 160 g/mol

Molar mass of hydrated compound = 250 g/mol

x/160 = 2/250

250x = 2 ×160

x= 2 × 160/250

x= 1.28 g

Answer:

10 grams of hydrogen

Explanation:

Fluorine has the highest electronegativity in comparison to other elements therefore, the F atom attracts electrons most strongly.

The electronegativity of an atom measures the tendency of an element to attract the bonded electrons pairs towards itself. The electronegativity of an atom is determined with respect to another bonded atom.

Electronegativity can be described as a chemical property of an atom or a functional group to attract electrons toward itself. The electronegativity of an atom depends on the atomic number and the distance of valence electrons from the charged nuclei.

When two different atoms are bonded through a bond. More electronegative will attract the electron density of the bond towards itself.

As we know, the electronegativity decreases as we move down the group in the periodic table. Fluorine is the most electronegative element in the periodic table therefore, Fluorine (F) will attract the electrons toward it most strongly.

Learn more about electronegativity, here:

brainly.com/question/17762711

#SPJ6

Answer:

16mL

Explanation:

Using the following formula;

CaVa = CbVb

Where;

Where

Ca = concentration/molarity of acid (M)

Va = volume of acid (mL)

Cb = concentration/molarity of base (M)

Vb = volume of base (mL)

According to the information provided in this question;

Ca (HCl) = 2M

Cb (NaOH) = 5M

Va (HCl) = 40mL

Vb (NaOH) = ?

Using CaVa = CbVb

Vb = CaVa/Cb

Vb = 2 × 40/5

Vb = 80/5

Vb = 16mL

Answer:

1/....

Explanation:

If we say acceleration 'a' is inversely proportional to mass 'm', then

a=1/m.

Answer:

A. Li= 5.6 g O2= 6.4 g

Explanation:

Lithium oxide, Li2O, is an oxide that contains 2 moles of Li and 1 mole of O per mole of oxide. To solve this question we must find the mass of each atom in the molecule as follows:

2Li = 2*6.941g/mol = 13.882g/mol

O = 1*16g/mol = 16g/mol

Molar mass Li2O:

16+13.882 = 29.882g/mol

The mass of lithium is:

12g * (13.882g/mol / 29.882g/mol) = 5.6g Li

And the mass of oxygen:

12g * (16g/mol / 29.882g/mol) = 6.4g O

Right answer is:

Answer:

The answer is ¹³₆C

Explanation:

searched it up

Answer:

Gold and pyrite both have a brilliant metallic luster, but are different tones of yellow. Gold is golden to silvery yellow, whereas pyrite is a pale to medium brassy yellow that sometimes tarnishes.

Explanation:

Answer:

An lonic bond because calcium is transferring Its electrons to the chlorine.

Explanation:

Metals usually form compounds with non-metals through ionic bonding.

Metals are electropositive elements which form ions by the loss of electrons, whereas non-metals are electronegative elements which form ions by the gain of electrons.

Compounds are formed when two or more elements combine together. The formation of compounds involves formation of bonds which may be either ionic or covalent bonds.

The type of bonding that exists between the a metallic calcium atoms and non-metallic chlorine atoms in calcium chloride, CaCl₂, is ionic bonding. In the process of formation of the compound, calcium atoms which have a valency of 2 readily donates their two valence electrons to chlorine atoms to form calcium ions, Ca²+. Each chlorine atoms having a valency of 1 accepts an electron to form chloride ions Cl-. Two chlorine atoms accept the two electrons donated by a calcium ion. Due to strong electrostatic forces of attraction between the calcium ion and the two chloride ions, the ionic compound CaCl₂ is formed.

Explanation:

It is known that like charges repel each other and unlike charges attract each other.

As the balloons are facing each other with like charges so they will repel each other. Hence, they will move apart.

But when balloons were moved further apart then interaction between them will decrease and then there will be no force of repulsion or force of attraction.

Answer: There are [tex]12.71 \times 10^{-9}[/tex] moles present in [tex]2.11 \times 10^{14}[/tex] molecules of LiBr.

Explanation:

According to the mole concept, there are [tex]6.022 \times 10^{23}[/tex] molecules present in 1 mole of a substance.

Hence, moles in [tex]2.11 \times 10^{14}[/tex] molecules of LiBr are calculated as follows.

[tex]Moles = \frac{2.11 \times 10^{14}}{6.022 \times 10^{23}}\\= 12.71 \times 10^{-9}[/tex]

Thus, we can conclude that there are [tex]12.71 \times 10^{-9}[/tex] moles present in [tex]2.11 \times 10^{14}[/tex] molecules of LiBr.