hi does anyone know what the answer to this is? i really need help

Answer: it’s the first one ☝️

Mass NEVER changes

Answer:

Three things that rely on the sun for energy is coal,oil, and natural gases

Explanation:

We use engery too cook our food that's an example of how gases are used.

We run our cars .Cars use oil.

And we use electricity for lights. You need coal for the electricity

Answer:  

*Sun sends oxygen so all living kind (humans, plants, animals etc.) can live

*The sun sends heat to the earth so it wouldnt freeze

*We can use the sun as to create solar energy

Explanation: I hope this helps <3

Answer:

Four general conditions necessary for natural selection to occur are: More organisms are born than can survive. Organisms vary in their characteristics, even within a species. Variation is inherited.

Answer:

Natural selection can lead to speciation, where one species gives rise to a new and distinctly different species. It is one of the processes that drives evolution and helps to explain the diversity of life on Earth.

Explanation:

Answer:

6.8 liters of propane gas will undergo a complete combustion with 34.0 L of oxygen gas.

Explanation:

Given;

combustion reaction of propane and oxygen;

C₃H₈ + O₂(g)  → CO₂(g)     + H₂O(g)

Balance the chemical reaction as follows;

C₃H₈ + 5O₂(g)  → 3CO₂(g)   +   4H₂O(g)

From the balanced equation;

1 mole of C₃H₈ ---------------- 5 moles of 5O₂(g)

x Liters of C₃H₈ ----------------- 34.0 Liters of O₂(g)

x = 34 liters / 5

x = 6.8 liters

Therefore, 6.8 liters of propane gas will undergo a complete combustion with 34.0 L of oxygen gas.

Answer: 2) Chloroform & Caustic potash

Explanation:

The carbylamine reaction is a kind of chemical test which is done to detect primary amines in an unknown solution. It cannot detect secondary and tertiary amines.

The reaction involves the heating with up of the unknown solution with alcoholic potassium hydroxide or caustic potash and the chloroform.

In the presence of primary amine, the production of isocyanide results.

Answer:

option 3

Explanation:

it is so because when both bulbs were there It took more electricity to charge both of them. now since only one is there it takes the power that is produced which made the other bulb glow and uses it for itself.

I'm sorry if u didn't understand

Answer:The main job of the innate immune system is to fight harmful substances and germs that enter the body, for instance through the skin or digestive system. The adaptive (specific) immune system makes antibodies and uses them to specifically fight certain germs that the body has previously come into contact with.

Answer:

1.4

Explanation took test

Answer:

its proprionic acid which do not cause any hazardous effect on environment it only effect internal body of human if it is ingested.

Explanation:

Answer:

This would give us Helium 4.

Explanation:

Lithium7 has 3 protons, 4 neutrons and 3 electrons.

Removing  1 Proton 1 electron and 2 neutrons would form an element with

2 protons 2 electrons and 2 neutrons.

This is Helium 4.

Answer: Should be A)

Explanation:

the size of planets effects the amount of gravitational force each planet has, like jupiter, it has the most gravity.

Answer:

yes

Explanation:

yes because the molar mass is an intensive property of the substance, that does not depend on the size of the sample. In the International System of Units (SI), the base unit of molar mass is kg/mol. However, for historical reasons, molar masses are almost always expressed in g/mol.

Answer:

Yes, if your calculating from grams to moles.

Answer:

Octahedral

Explanation:

Recall that according to Valence Shell Electron Pair Repulsion Theory(VSEPR) the shape of a molecule is based on the number of electron pairs on the outermost shell of its central atom.

In BrF4^-, the bromine atom is surrounded by 6 electron pairs. Four bond pairs and two lone pairs.  This means a total of six regions of electron density.

According to VSEPR Theory,  BrF4^- has an octahedral electron geometry and its the molecular geometry will be square planar  since it is of the type AX4E2.

An image of the  BrF4^- is attached below.

Noble gas located in the region D

Noble gas are located in group 18 in the periodic table consisting of helium (He), neon (Ne), argon (Ar), krypton (Kr), xenon (Xe), have a stable electron configuration where the valence electrons are 8(full outer shell of electrons), so it is very hard to react because of its stability

If we look at the periodic system of the elements, the noble gases are on the far right, so that in Figure 8 it is located in area D

And the other region :

A : alkali elements(group 1),

B : alkaline earth elements(group 2)

C : halogen elements(group 17)

Answer:

Helium, this noble gas has the least density at STP

Explanation:

Answer: D

Explanation: P = W/t

W = F d

When dividing, if you have a large number over a small, you get a large number. We want a small number, so we want the opposite for our P : W/ t formula. We want a small Work and a large time.

Right off the bat, the two with the least time aren't right then.

From there, we can estimate how much work it would take using the W = F d equation. If there is a small distance, there is less work, which is what we want to achieve a small work over large time.

So, the choice with the most time and the least distance should be correct.

Answer:

Osmosis

Explanation:

Water is very essential for the body. When we drink water, our blood cells absorbs water from the body. This happen by a process called as osmosis process. Osmosis is type of diffusion process.

Water along with oxygen and carbon dioxide are some of the simple molecules that moves into the blood cell. Osmosis is the process by which water molecules passes into the cell bodies through its semi permeable membrane.    

Answer:

657.2 Hz

Explanation:

Answer:

13.75

Explanation:

Density is equal to mass divided by volume. 110/8 = 13.75

no it cannot I hope I helped

Answer:

Can not

Explanation:

Because both are salts of sodium and hydroxide

Answer:it's either the first or second one

Explanation:

the layers of the earth

Answer:

Explanation:

plz mark as brainilist

Answer:

BELOW !!

Explanation:

Chemical energy in food

As the bonds between the atoms in food loosen or break, a chemical reaction takes place, and new compounds are created. The energy produced from this reaction keeps us warm, helps us move, and allows us to grow. Different foods store different amounts of energy.

Answer:

Directly by the sun

Answer:

A colloid is a heterogeneous mixture in which the dispersed particles are intermediate in size between those of a solution and a suspension. The particles are spread evenly throughout the dispersion medium, which can be a solid, liquid, or gas.

Explanation: