(b)
Huiting wanted to find out the hardness of two materials H and F. She used a
rounded object made of material G and forced it into each material with the
same force. The results of her experiment are shown below.
rounded object of
material G
rounded object
of material G
3 mm
1 mm
object of
material H
object of
material F
List materials F, G, H in increasing order of hardness. Explain your answer.
[2]​

Answer:

7.2

Explanation:

you first have to find the number of moles of nitrogen dioxide by using the number of moles for calcium nitrate and the mole to mole ratios

number of moles of calcium nitrate=mass/mm

=16.4/102

=0.16g/mol

then you use the mole to mole ratios

2 : 4

0.16: x

2x/2=0.64/2

x=0.32g/moles of nitrogen dioxide

then you use the formula for the volume

v=22.4n

=22.4×0.32

=7.2

I hope this helps

Answer:

C 760 mm of hg

because this is the atmospheric pressure at sea level

Answer: 1.86*10^-7M

Explanation:

Answer:

B. 1.86 x 10^-7 M

Explanation:

Explanation : số mol glucose 3.8M là :

n = Cm . V = 3.8 . 25 =95

=> Cm khi pha loãng = [tex]\frac{n}{V}[/tex] = [tex]\frac{95}{250}[/tex] = 0.38M

According to molar concentration, the  concentration of a solution formed by diluting 25.0 ml of a 3.8 M glucose solution to 250 ml is 0.38 M.

Molar concentration is defined as a measure by which concentration of chemical substances present in a solution are determined. It is defined in particular reference to solute concentration in a solution . Most commonly used unit for molar concentration is moles/liter.

The molar concentration depends on change in volume of the solution which is mainly due to thermal expansion. Molar concentration is calculated by the formula, molar concentration=mass/ molar mass ×1/volume of solution in liters.

In terms of moles, it's formula is given as molar concentration= number of moles /volume of solution in liters.In case of 2 solutions given it is calculated as M₁V₁=M₂V₂,on substitution, M₂=3.8×25/250=0.38 M.

Thus,  the  concentration of a solution formed by diluting 25.0 ml of a 3.8 M glucose solution to 250 ml is 0.38 M.

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Answer:

yes

Explanation:

3Ag(No3) (aq) +FeCl3(aq) -->Fe(NO3)3(aq)+3AgCl(s)

1. Unit of pressure called a derived unit because it is a combination of base units (kg·m^-1·s^·2).

2. We measure the volume of milk by a instrument called Milk Lactometer.

Answer:

i is the correct answer.

Explanation:

the RAM of aluminum is indeed 27. And since the RAM of substances are measured in terms of the C-12 isotope then R indeed explains why the RAM Al is 27.

Answer:

B. Protons and Neutrons

Answer:

Option"B" is correct.

MARK ME BRAINLISTS

Answer:

16 g

Explanation:

Step 1: Write the balanced equation

2 Na + Cl₂ ⇒ 2 NaCl

Step 2: Identify the limiting reactant

The theoretical mass ratio (TMR) of Na to Cl₂ is 46:71 = 0.65:1.

The experimental mass ratio (EMR) of Na to Cl₂ is 10:10 = 1:1.

Since EMR > TMR, Cl₂ is the limiting reactant

Step 3: Calculate the mass of NaCl produced

The theoretical mass ratio of Cl₂ to NaCl is 71:117.

10 g Cl₂ × 117 g NaCl/71 g Cl₂ = 16 g NaCl

Answer:

Potentials of any other electrodes are compared with that of the standard hydrogen electrode at the same temperature. Hydrogen electrode is based on the redox half cell: 2 H+(aq) + 2 e− → H2(g)..

Answer:

1 Ca(NO3)2

Calcium- Ca, Valency 2

Nitrate- NO3, Valency 1

AFTER CRISS CROSS:

Ca1(NO3)2

Ca(NO3)2

2 sodium bicarbonate = NaHCO3

Na = Sodium = (Na)+

HCO3 = bicarbonate = (HCO3) -

Na HCO3

3 magnesium   nitrite

   +2                 _ 1

Mg2(NO3)2

4 Na    Cl

    +1    _1

formula NaCl

5 hydrogen         sulphide  

H                       SO4

+1                       _2

formula H2SO4

6  H    Cl

  +1     _1

HCl

7 AL2     HSO4

  +2        -2

AL2(HSO4)3

8  NH4   Cl

   +1      _1

NH4Cl

9 NH4     SO4

  +1           _2

(NH3)2SO4

10  H   NO3

    +1    _1

HNO3

Explanation:

here's the answer to your question

1 meter = 1000 km

2500 meter = 2500/1000 km

= 2.5 km

Answer: A reaction element are those elements that can take part in a chemical reaction.

Explanation:

An element is made up of atoms that has the same atomic number. It is the basic material of which all matter is composed of. These elements cannot be broken down further into smaller substances by any chemical reaction. Each element has a unique number of protons in its atom. For example,

--> a hydrogen atom has 1 proton,

--> a Helium atom has 2 protons,

--> a Lithium atom has 3 protons, and

--> a carbon atom has 6 protons.

A chemical reaction on the other hand involves rearrangement of the constituent atoms of reactants to create different substances as products. The bonds between atoms are either broken or created to form new molecules. There are different types of chemical reaction which includes:

--> Decomposition reaction

--> Neutralization reaction

--> single displacement reaction and

--> combustion reaction.

Explanation:

freezing point depression is a phenomenon that describes why adding a solute or solvent results in the lowering of the freezing point of the solvent

The reaction between H2SO4 in a mixture of KI and MnO2 yields iodine which reacts with hypo solution​ by titration and the iodine is decolorized.

Iodine is decolorized.

The first reaction stated in the question occurs as follows;

2 KI (aq) + 2 H2SO4 (aq) + MnO2 (s) → MnSO4 (aq) + K2SO4 (aq) + I2 (s) + 2 H2O (l)

The reaction here is the formation of iodine from MnO2 and KI in the presence of dropwise H2SO4.

Hypo is the common name of sodium thio-sulphate or sodium hypo-sulfite.

The equation of the titration reaction is;

2Na2S2O3 + I2→ Na2S4O6 + 2NaI

When this reaction takes place, iodine is decolorized due to its reduction to I^-.

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Answer:

Because elements of group  1 does not have stable electronic configuration and elements of group 18 have stable electronic configuration.

Explanation:

Because elements of group 1 do not contain stable electronic configuration and elements of group 18 include stable electronic configuration.

Group 1 elements contain the alkali metals, Li, Na, K, Rb, Cs, and Fr. The alkali metals exist all soft, shiny, and metallic when cut. They react efficiently with water, have low melting points and densities, and are good conductors of electricity. They all include one valence electron that they lose easily to form ions. Noble gas exists as any of the seven chemical elements that create up Group 18 (VIIIa) of the periodic table. The elements exist as helium (He), neon (Ne), argon (Ar), krypton (Kr), xenon (Xe), radon (Rn), and oganesson (Og).

The element of group 1 exist as reactive but those of group 18 exist as inert Because elements of group 1 do not contain stable electronic configuration and elements of group 18 include stable electronic configuration.

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Answer:

Below!

Explanation:

Isotopes are elements with a similar chemical makeup and the same atomic number, but a different atomic mass and number of neutrons . An example of this would be carbon-12, carbon-13, and carbon-14. Three isotopes of the element carbon that have the same 6 protons but have a different neutron count. A simple way to explain isotopes would be to say that they are just different "versions" of an element.

Hope this helps ya! Best of luck <3

Answer:

1;1, 2;1, 3;1, 1;2, 1;1, 3;2, 1;3, 2;3, 1;1.

I hope this will help.

Answer:

This is what the answer looks like

Explanation:

The correct lewis structure of methane(CH4)

C. H:C:H:H

Answer:

These are compounds.

Explanation:

As it is formed by chemically bonding of two elements C ( carbon) and H (hydrogen) .

Answer:

Butane and benzene are both compounds. They contain multiple elements bonded together in a specific ratio. Kerosene and gasoline are mixtures because they are combinations of several compounds. Oxygen is an element because it is made up of only one type of atom.

Explanation:

Answer:

palisade cell due to presence of chloroplasts

Answer:

liquid form

Explanation:

am i right? if right like

Answer:

semi-liquid at room temperature

Answer:

In a physical change the appearance or form of the matter changes but the kind of matter in the substance does not. However in a chemical change, the kind of matter changes and at least one new substance with new properties is formed.

Answer:

–2400 N

Explanation:

This is a physics question. However, the answer to the question is given below.

We'll begin by converting 36 Km/hr to m/s. This can be obtained as follow:

3.6 Km/hr = 1 m/s

Therefore,

36 Km/hr = 36 Km/hr × 1 m/s / 3.6 km/hr

36 Km/hr = 10 m/s

Thus, 36 Km/hr is equivalent 10 m/s.

Next, we shall determine the acceleration of the car. This can be obtained as follow:

Initial velocity (u) = 10 m/s

Final velocity (v) = 0 m/s

Time (t) = 5 s

Acceleration (a) =?

a = (v – u) / t

a = (0 – 10) / 5

a = – 10 / 5

a = –2 m/s²

Finally, we shall determine the force required to stop the car. This can be obtained as follow:

Mass (m) = 1200 Kg

Acceleration (a) = –2 m/s²

Force (F) =?

F = ma

F = 1200 × –2

F = –2400 N

NOTE: The negative sign indicate that the force is in opposite direction to the motion of the car.

The empirical formula is the simplest formula of a chemical compound.

To find the empirical formula, we take the following steps;

1) O - 88.10/16,      H - 11.190/1

  O - 5.5,               H - 11.19

  O - 5.5/5.5,        H - 11.19/5.5

  O -  1,                 H - 2

Empirical formula = OH2

2) C - 41.368/12  H - 8.101/1,   N - 32.162/14,   O - 18.369/16

   C - 3,               H - 8,           N - 2,                  O - 1

   C - 3/1,            H - 8/1          N - 2/1                 O - 1/1

    C - 3,             H - 8,           N - 2,                   O - 1

Empirical formula = C3H8N2O

To obtain the molecular formula where n = number of atoms of each element;

Molecular weight = 174.204 g/mol

[ 3(12) + 8(1) + 2(14) + 16]n = 174

n= 174/88

n = 2 (to the nearest whole number)

Hence, we have;

[C3H8N2O]2

The molecular formula is C6H16N4O2

3)  C - 19.999/12,  H - 6.713/1,   N - 46.646/14,   O - 26.641/16

    C - 2,                H - 7,            N -  3,                 O - 2

    C - 2/2,            H - 7/2,         N -   3/2,             O - 2/2

    C - 1,                H - 4,            N -  2,                  O - 1

Empirical formula - CH4N2O

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