When Robert Hooke looked at cork through a microscope , he named what he saw “cells” because__________
a. He could barely see what he was looking at
b. The cork looked like shells
c. They were the holes of the cork
d. The cork looked like tiny rectangular rooms

Answer:

A. Hydrogen Bonding

Explanation:

Answer:

Hydrogen bonding

Explanation:

because it has the highest electronegative force

The potential energy : PE = 5.88 x 10⁻³ J

Given

height = h = 20 cm = 0.2 m

mass = 3 grams = 3 x 10⁻³ kg

Required

The potential energy

Solution

The energy produced from its position is called potential energy (PE)  

which can be formulated as:  

PE = m. g. h

Input the value :

PE = 3 x 10⁻³ x 9.8 x 0.2

PE = 5.88 x 10⁻³ J

Answer:

Burning of fossil fuels

Cutting of tress

Also CO2 is produce in industries like cement manufacturing.

Explanation:

Answer:

A.) pure substance

Explanation:

edge 2021

Answer:

True

Explanation:

The arrangement of three groups COOH, CO, OH in the order of reducing boiling point is as follow -

 COOH > OH > CO

COOH gets strongly polarised due to the presence of electron withdrawing carboxy group and hence have strong H+ bonds as compared to that of alcohol.

Hence the given statement is true.

100g/220g*100 is the correct answer- I took the test

Answer:

answer:

given;

total gram=70+50+100=220g

total gram of chocolate=100g

percentage composition of chocolate=total gram of chocolate/total gram ×100%

=100g/220g ×100 is your answer

Answer:

28 meters

Explanation:

molarity = moles of solute/liters of solution

We know the moles of solute: 0.875 moles of glucose. We can easily determine the liters of solution by using the mass of water given (1.5 kg) and the density of water (approximately 1 kg/L): they're, for all intents and purposes, equal (the approximation isn't large enough to be appreciable here, nor would the volume of the solution appreciably change since the solute is a solid that will dissolve into the solvent). So, we have 1.5 L of solution.

Now, we plug in what we have:

molarity = 0.875 moles of glucose/1.5 L of solution = 0.58 M glucose

The answer is provided to two significant figures since we're given the mass of water to two significant figures.

Answer:

the answer is 262.216229

Explanation:

:)

Answer:

84.3139 grams.

Explanation:

Answer:

A

Explanation:

3.59 mol

1.836 x 10 ²⁵ molecules

Given

230 g SO2

30.5 moles LiNO3

Required

moles and molecules

Solution

mol = mass : molar mass

1 mol = 6.02 x 10²³ particles(molecules, atoms, ions)

1. 230 g x 1 mol/64,066 g  =3.59 mol

2. 30.5 moles x 6.02 x 10 ²³ molecules / 1 mol = 1.836 x 10 ²⁵ molecules

Answer:

for points

Explanation:

loll

Answer:

5

Explanation:

Given that the formula is;

1/λ= R(1/nf^2 - 1/ni^2)

λ = 93.7 nm or 93.7 * 10^-9 m

R= 1.097 * 10^7 m-1

nf = ?

ni = 1

From;

ΔE = hc/λ

ΔE = 6.63 * 10^-34 * 3* 10^8/93.7 * 10^-9

ΔE = 21 * 10^-19 J

ΔE = -2.18 * 10^-18 J (1/nf^2 - 1/ni^2)

21 * 10^-19 J = -2.18 * 10^-18 J (1/nf^2 - 1/ni^2)

21 * 10^-19/-2.18 * 10^-18 = (1/nf^2 - 1/1^2)

-0.963 = (1/nf^2 - 1)

-0.963 + 1 = 1/nf^2

0.037 = 1/nf^2

nf^2 = (0.037)^-1

nf^2 = 27

nf = 5

Answer:

Theoretically you could be totally unrelated to your sister or share the exact same DNA as your brother. But because we are talking about so much DNA and so many different possible combinations, the percentage usually comes out to about 50%. Think about it like flipping a coin.

Explanation:

Explanation:

Theoretically you could be totally unrelated to your sister or share the exact same DNA as your brother. But because we are talking about so much DNA and so many different possible combinations, the percentage usually comes out to about 50%. 

Answer:

21.3g of Fe(NO₃)₃ are required to produce the same depression in freezing point of solution.

Explanation:

Freezing point depression is a colligative property which indicates, in determined mixture, the freezing point of solution is lower that the freezing point of the solvent, according the amount of solute.

Formula is: ΔT = Kf . m . i

Kf is the cryoscopic constant, which is particular for each solvent. We do not have that data, so we need to find it out in order to solve the question:

ΔT = Freezing point of pure solvent - Freezing point of solution.

This data is known → 6.40°C

m, means molality, moles of solute in 1kg of solvent. Let's get the moles of benzamide: 42.5 g . 1mol / 121g = 0.351 moles

m = 0.351 mol / 0.5kg = 0.702 m

As benzamide is an organic compound i, = 1. i are the number of ions dissolved in solution. Let's find out Kf:

6.40°C = Kf . 0.702 m . 1

6.40°C /0.702m = 9.11 °C/m.

Let's go to the next question.

ΔT is the same → 6.40°C

But this is, an inorganic salt, a ionic salt: Fe(NO₃)₃ →  1Fe³⁺  + 3NO₃⁻

For this case, we have 1 mol of Iron(III) and 3 nitrates, so i = 4

Let's replace data: 6.40°C = 9.11 °C/m . m . 4

6.40°C / (9.11 m/°C . 4) = 0.176 m

This data represents that, in 1 kg of solvent we have 0.176 moles of nitrate.

Mass of solvent X required in this case is 0.500 kg, so, the moles that are contained are: 0.500 kg . 0.176 mol/kg = 0.088 mol

Let's determine the mass of salt: 0.088 mol . 241.85g /1mol = 21.3 g

Answer:

[tex][PCl_3]=[Cl_2]=0.068M[/tex]

[tex][PCl_5]=0.385M[/tex]

Explanation:

Hello!

In this case, since the equilibrium expression for the considered equation is:

[tex]Kc=\frac{[PCl_5]}{[Cl_2][PCl_3]}[/tex]

Which can be written in terms of the reaction extent and the ICE chart and the initial concentrations of 0.453 M as shown below:

[tex]83.3=\frac{x}{(0.453M-x)(0.453M-x)}[/tex]

We can solve for x as follows:

[tex]x=0.385M[/tex]

In such a way, we obtain the following concentrations at equilibrium:

[tex][PCl_3]=[Cl_2]=0.453M-0.385M=0.068M[/tex]

[tex][PCl_5]=0.385M[/tex]

Best regards!

[H⁺]=6.696 x 10⁻⁵

pH = 4.174

Given

The concentration of 0.000295 M (2.95 x 10⁻⁴ M) butanoic acid solution

Required

the [H+]  and pH

Solution

Butanoic acid is the carboxylic acid group. Carboxylic acids are weak acids

For weak acid :

[tex]\tt [H^+]=\sqrt{Ka.M}[/tex]

Input the value :

[H⁺]=√1.52 x 10⁻⁵ x 2.95 x 10⁻⁴

[H⁺]=6.696 x 10⁻⁵

pH = - log [H⁺]

pH = - log 6.696 x 10⁻⁵

pH = 5 - log 6.696

pH = 4.174

Answer:

110g/mol is the molar mass of compound A

Explanation:

The osmotic pressure of a solution could be obtained using the equation:

π = i*M*R*T -Solving molarity we can find the molar mass of the solute A-

Where π is osmotic pressure (7.38atm)

i is Van't Hoff's factor (1 for nonelectrolytes)

M is molarity (Our incognite)

R is gas constant (0.082atmL/molK)

T is absolute temperature (25°C + 273.15 = 298.15K)

Computing the values:

7.378atm = 1*M*0.082atmL/molK*298.15K

0.3018 mol/L is the concentration of the solution.

The volume of the solution is 15mL = 0.015L. Moles of the solute are:

0.3018 mol/L * 0.015L = 4.527x10⁻³ moles

Molar mass is the ratio between mass of the compound (0.50g) and the moles (4.527x10⁻³ moles). That is:

0.50g / 4.527x10⁻³ moles =

Sulfur act as a reducing agent and chlorine acts as an oxidizing agent.

The charge is based on the number of electrons assigned to an atom as compared to the neutral atom

Given reaction:-

[tex]S+Cl_2 \rightarrow SCl_2[/tex]

The oxidation state of sulfur in the left side is 0, but in right side is +2. So, sulfur is oxidized. The oxidation number of Cl in the reactant side is 0 and n the product side is -1. So, Cl acts as oxidizing agent.

To know more about:-

brainly.com/question/13182308

Answer:

Below 7

Explanation:

The equivalence point, or stoichiometric point, of a chemical reaction is the point at which chemically equivalent quantities of reactants have been mixed(Wikipedia).

For a strong acid-weak base titration, the pH at the equivalence point is usually below 7. This owes to the fact that a conjugate acid  is produced in the course of the reaction which interacts with water to produce hydronium (H3O+) ions.

Answer:

7

Explanation:

i did my research and from what i found its 7.

Answer:

electromagnetic field

Answer:

Probably Alkaline

Explanation:

Not sure at all.

Decomposition: A substance breaks down to smaller species.

Answer:

d. Mass is the measure of the earth’s gravitational attraction of a body

This is FALSE. Mass is the measure of matter than an object contains.

Explanation:

b. An atom is the smallest particle of an element that still contains properties of the original element.

This is True

c. Gases can be colorless or colored

This is True

d. Mass is the measure of the earth’s gravitational attraction of a body

This is FALSE. Mass is the measure of matter than an object contains.

e. A pure substance has a fixed composition.

This is True.

Answer: C6H12O6 is formed by a covalent bond, the rest of the options are formed by ionic bonds.

Answer:

a. True

Explanation:

The bond angle for methane is the angle determined by two consecutive hydrogen atoms and the central carbon atom.

Methane, a tetrahedron has the structural formula:

                             H

                              |

                    H  -   C   -  H

                              |

                             H            Methane, CH4

The bond angle is the angle between the H-C-H atoms and is 109.5degrees.