CHEMISTRY MIDDLE SCHOOL

What is the main organ of the circulatory system? arteries

veins

heart

capillaries

Answers

Answer 1
Answer:

Explanation:

your heart is the main organ of the circulatory system

Answer 2
Answer: The heart are the main organ.
arteries, veins and capillaries are the one that travels blood around the body

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COLLEGE

How does the addition of salt to solid ice affect the melting transition from solid to liquid? A. The amount of energy absorbed would not change during the plateau.
B. It would need to absorb less energy during the plateau in order to melt.
C. It would need to absorb more energy during the plateau in order to melt.
D. There would be no plateau, the salt would cause the solid to immediately melt.

Answers

Answer:

The water would need to B. absorb less energy during the plateau in order to melt.  

Explanation:

Salt when added to ice lowers the freezing point of the ice. So, if ice is added to the solid ice it doesn't let it to freeze rather the temperature of water may fall but it won't freeze.

For melting, it needs less energy after adding salt because salt itself absorbs the energy from the surroundings to help the phase transition of water from solid to liquid.

Answer: C. It would need to absorb more energy during the plateau in order to melt.


Explanation:

adding salt lowers the freezing point, meaning it needs to absorb more energy from its surrounding in order to melt.

HIGH SCHOOL

Which is a stronger base, HSO4 or H2PO4

Answers

An acid is an H+ donor while a base is an H+ acceptor. When looking at HSO4- and H2PO4- it can be said that since HSO4 gives up an H+ easier it is a better acid than H2PO4-. Then it can also be said that H2PO4- is then a better or stronger base than HSO4-
HIGH SCHOOL

What amount of ammonia, NH3(g), can be produced from 15 mol of hydrogen reacting with excess nitrogen? 3 H2(g) + N2(g) → 2NH3 (g)

Answers

Answer:

10mol

Explanation:

3H2 + N2 -> 2NH3

Stoichiometry is a tool that chemists can use to find the amount of substance present in any part of a reaction. The arrow (->) suggests that the reaction goes to completion (100%), so assume that left side = right side.

3H2

15 mol

You can divide the amount of moles by the coefficient to find the number of moles when you have a coefficient of 1. This number can then be used to find the value of moles for the rest of the products/reactants:

15/3=5mol

NH3 has a coefficient of 2, so we have to multiply the value we got (5mol) by 2. This results in having 10mol of ammonia as the end result.

MIDDLE SCHOOL

fingernail-polish remover (mostly acetone) is a liquid at room temperature. Would you describe acetone in the gaseous state as a vapor or a gas? explain your answer

Answers

A gas is defined as a substance that exists in the gasous state at room tempeature. A vapor, however, is the gasous state of a substance this generally a liquid at room tempeature. So it is a vapor.
HIGH SCHOOL

Balance the equation The synthesis of carborundum for sandpaper. _____ SiO2 + _____ C → _____ SiC + _____ CO

Answers

Answer:

balanced chemical equation is

2 SiO₂ + 3 C₂ = 2 SiC + 4 CO

MIDDLE SCHOOL

how many moles of potassium would you need to prepare 1200 grams of 5.0% potassium sulfate (m/m) solution

Answers

The  moles  of  potassium  that  you  would    need  to  prepare  1200 g  of  5% potassium   sulfate solution  is    1.538 moles

calculation
  calculate  the mass  potassium using  the below formula

%M/M =  mass  of the  solute(potassium)/mass of the  solvent (potassium  sulfate solution)

let  the  mass  of  potassium be represented by  Y

then  convert %  into fraction  = 5/100

5/100 =  Y/1200
cross  multiplication
100y =  6000
divide  both side by 100

Y=  60 g

moles of potassium =mass/molar  mass

= 60/39=1.538
HIGH SCHOOL

The balance equation for HCL + Ca (OH )2--------CaCl2 +H2O

Answers

2HCl + Ca(OH)₂ = CaCl₂ + 2H₂O
COLLEGE

Write a balanced equation for the reaction that occurs in each of the following cases: (a) Potassium metal is exposed to an atmosphere of chlorine gas. (b) Strontium oxide is added to water. (c) A fresh surface of lithium metal is exposed to oxygen gas. (d) Sodium metal reacts with molten sulfur.

Answers

Balanced equation is that number of ions in the LHS is equal to RHS. In the reaction elements is conserved. i.e. Conservation of Mass.

What is law of conservation of mass?

The Law of Conservation of Mass basically states that matter can neither be created nor destroyed.

From the reaction, we can see that left hand side are reactant and right hand side is products.

a) Potassium metal is exposed to an atmosphere of chlorine gas.

2K(s) + Cl2(g) ==> 2 KCl(s)

(b) Strontium oxide is added to water.

SrO(s) + H2O(aq) ==> Sr(OH)2(aq)

(C) A fresh surface of lithium metal is exposed to oxygen gas.

4Li(s) + O2(g) ==> 2Li2O(s)

(d) Sodium metal reacts with molten sulfur.

2Na(s) + S (l) ===> Na2S

Thus above, reactions are balanced.

To find more about Reaction, refer the link below:

brainly.com/question/17434463

#SPJ2

Answer: The equations of the above reactions are shown below

Explanation:

(a)

2K(s) + Cl2(g) ==> 2 KCl(s)

(b)

SrO(s) + H2O(aq) ==> Sr(OH)2(aq)

(c)

4Li(s) + O2(g) ==> 2Li2O(s)

(d)

2Na(s) + S (l) ===> Na2S

HIGH SCHOOL

The Periodic Table of Elements is organized by the number of:

Answers

The classic Periodic Table organizes the chemical elements according to the number of protons that each has in its atomic nucleus. Hope this helped :)
The answer to your question is Atomic Number.
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