Which statement about the alkali metals is correct?
A. They are usually gases.
B. They are extremely unreactive.
C. They are located in the left-most column of The Periodic Table
D. They form negative ions with a -1 charge

Answer: D. At high temperatures and low pressures

Explanation:

At low temperature and high pressure, the kinetic energy of gas molecules is negligible and molecules will have negligible forces of attraction. So real gases will behave least like an ideal gas under such conditions.

At high temperature and low pressure, energy due to intermolecular forces becomes less important in comparison to the kinetic energy of particles. The size of molecules also become less significant than the empty space between the gas molecules. So real gases behave in a similar manner to ideal gases at high temperature and low pressure.

Answer:

B.) Adding a source of carbon dioxide to the water.

Explanation:

I had that question too.

When any chemical equation is not balanced then that is known as skeletal chemical equation. We need to balance it because as we know that mass can neither be created nor be distroyed and also the number of atoms on the reactant side should always be equal to the compounds on the product side .

Answer:

Moles of oxygen molecules produced = 3 mol

Explanation:

Given data:

Moles of oxygen molecules produced = ?

Number of moles of lead oxide decomposed = 6 mol

Solution:

Chemical equation:

2PbO₂          →        2PbO + O₂

Now we will compare the moles of oxygen and lead oxide.

                   PbO₂        :          O₂

                      2           :            1

                      6           :           1/2×6 =3 mol

three moles of oxygen molecules are produced.

Answer:

b

Explanation:

Answer:

2FeBr₃ + 3H₂SO₄ ⇒ Fe₂(SO₄)₃ + 6HBr

Explanation:

match the products and reactants of both sides.

it can be be be be be ebe be e e

According to the collision theory, the following criteria must be met in order for a chemical reaction to occur: Molecules must collide with sufficient energy, known as the activation energy, so that chemical bonds can break.

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Collision theory expresses that substance responses (in the gas stage) happen because of crashes between reactants.

To really start a reaction, impacts should be adequately lively (dynamic energy) to break compound bonds; this energy is known as the Activation energy. As the temperature rises, atoms move quicker and impact all the more energetically, significantly improving the probability of bond breakage upon crash.

Find more information about Activation energy here:

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Answer:

I, II, III,IV

Explanation:

Metals are known to possess metallic bonds. In a metallic bond, electro-positive metals loose electrons which form a cloud of electrons which exerts an attractive force on the positive metallic ions. This attractive force holds the metal atoms together in the crystal lattice.

The physical properties of metals include;

I. thermal conductivity

II. electrical conductivity

III. malleability

IV. ductility

Hence, substances that exhibit properties I-IV are metals and have metallic bonds.

The following properties which a substance that has metallic bonding

normally have include

Metals are elements which have metallic bonding which is always strong as

it helps to form a lattice.

Metals are good conductors of heat and electric current , they can also be

bent in to different shapes . This means it has all the properties listed above.

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Prevailing winds bring air from one type of climate to another. For example, warm winds that travel over water tend to collect moisture as they travel; the water vapor in the air will condense as it moves into colder climates, which is why temperate coastal areas often receive heavy rainfall.

Hope it Helps! T^T

Explanation:

Scientific knowledge allows us to develop new technologies, solve practical problems, and make informed decisions, both individually and collectively.

Answer:

If we had more scientific knowledge, we would be able to increase the productivity of life-saving equipment that provides a longer life for us

be able to make more sensible and informed decisions

make more achievements in studies and be more accurate etc..

Hope this helps<3

Answer:

Are composed together

Explanation:

Human teeth are made up of four different types of tissues.

Answer:

E = 4.78×10^−19 J

Explanation:

The chemical equation for the energy of a photon is given by:

E =hν , where h is the Planck constant and ν is the frequency.

E =hν = 6.626×10^−34 Js × 7.21×10^ 14

s−1 = 4.78 × 10^−19 J

Answer:

A. 4.78 x 10-19 J

Explanation:

A P E X

Mass of H₂SO₄ : 69,972 g

A mole is a number of particles(atoms, molecules, ions)  in a substance

This refers to the atomic total of the 12 gr C-12  which is equal to 6.02.10²³, so 1 mole = 6.02.10²³ particles  

Can be formulated :

N = n x No

N = number of particles

n = mol

No = 6.02.10²³ = Avogadro's number

moles of H₂SO₄ :

[tex]\tt mol=\dfrac{N}{No}\\\\mol=\dfrac{4.3\times 10^{26}}{6.02\times 10^{23}}\\\\mol=7.14\times 10^2[/tex]

mass H₂SO₄ (MW=98 g/mol) :

[tex]\tt mass=mol\times MW\\\\mass=7.14.10^2\times 98\\\\mass=69,972~g[/tex]

Given :

The atomic number of Arsenic (As) is 33.

The average atomic mass is 74.92 amu.

To Find :

A neutral arsenic atom will have protons.

Solution :

We know, atomic mass is the sum of number of protons and neutrons.

Also, atomic number is the number of protons present in an atom.

Therefore, a neutral arsenic atom will have 33 protons.

Answer:

A.  Sound travels slower in air because of the large distance between air particles

Explanation:

Sound is a mechanical wave that requires a medium for its propagation. Without a medium, sound cannot go through easily or readily. This implies that sound cannot be propagated through a vacuum.

Answer:

About 500

Explanation:

Bc i used my calc

Answer:f

Explanation:

Answer:

THE 3 third one

Explanation:

Answer:

6O₂

General Formulas and Concepts:

Chemistry/Biology

Explanation:

Most of the equation comes from the Photosynthesis Equation. Plants take in water and carbon dioxide and sunlight (energy) to produce glucose and oxygen. When we balance the equation and predict reaction. we should get   6O₂ as our answer.

Answer:

Reduce, reuse, and recycle your waste and trash. Protecting the environment helps protect the wetlands, especially since trash can make its way into the water. The best and easiest way to protect the environment is by limiting your household waste.

Uranium-232 will remain 11.72 g

The atomic nucleus can experience decay into 2 particles or more due to the instability of its atomic nucleus.  

Usually radioactive elements have an unstable atomic nucleus.  

The main particles are emitted by radioactive elements so that they generally decay are alpha (α), beta (β) and gamma (γ) particles  

General formulas used in decay:  

[tex]\large{\boxed{\bold{N_t=N_0(\dfrac{1}{2})^{T/t\frac{1}{2} }}}[/tex]

T = duration of decay  

t 1/2 = half-life  

N₀ = the number of initial radioactive atoms  

Nt = the number of radioactive atoms left after decaying during T time

t 1/2 = half-life  = 68.8 years

T = duration of decay  = 344 years

No= initial sample = 375 g

Uranium-232 remain :

[tex]\tt Nt=375.\dfrac{1}{2}^{344/68.8}\\\\Nt=375.\dfrac{1}{2}^5\\\\Nt=11.72~g[/tex]

Answer: Sugar

Explanation: Because after photosynthesis (Carbon dioxide, water, and sunlight) react, they make two products. Glucose (A sugar) and Oxygen.

Answer: Renewable becuase the trees can be cut and then replanted.

Explanation:

Non-Renewable resources are resources that cannot be replenished easily through natural process. These are the sources which are used in wise manner so that they do not get depleted. For example: coal, petroleum etc.

Renewable resources are resources that can be replenished overtime through natural process.These are the sources which never depletes completely. For example: bio mass energy, solar energy etc.

As trees can be replenished easily through natural process but it takes a long time for it to occur, it is a renewable source.