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Answer:

B

Explanation:

Isotopes have the same number of protons but different number of neutrons.

The true statement is,

So, option C is correct one.

The isotopes have different physical properties like freezing point , mass, melting or boiling point etc because they have different mass number .

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Answer: D. the number of protons

Explanation: The number of protons shows you what the Atomic number of an element is on the Periodic table of elements.

The identity of an element is primarily determined by the number of protons it possesses. The Option C.

Each element on the periodic table has a unique number of protons in its nucleus which is referred to as its atomic number. This fundamental property of an element distinguishes it from other elements and determines its place on the periodic table.

While number of neutrons and electrons can vary within an element, it is the number of protons that defines its identity. Thus, the correct answer is C: the number of protons.

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Answer: Johannes Kepler

Answer:

i believe the answer us kepler

Explanation:

Al= [Ar] 3s^2 3p^1

for the third period the principal quantum number is n=3. the third

Answer:

Explanation:

Given:

Amount in calories = 450 calories

Amount in joules = 3.5 × 100 joules

Find:

Computation:

We know that,

1 calories = 4.184 joules

So,

Amount in calories = 450 calories

= 450 × 4.184

= 1,882.8 joules

Amount in joules = 3.5 × 100 joules

=  [3.5 × 100] / 4.184

= 83.652 calories

Answer:

D. electron

Explanation:

Answer: 89.57 %

Hope it helps

Explanation:

Answer:

1.29* 10^2

Explanation:

multiply them and then round

Answer:

Well one characteristic is electical energy transforms into  thermal energy and gases and the state of matter(one of the distinct form i which  matter exist)

THIS IS THE COMPLETE QUESTION BELOW

46.9 gram sample of a substance has a volume of about 3.5 centimeters3. It is solid at a room temperature of 23ºC. Out of the four substances whose properties are given, which is the most likely identity of this substance?

Substance Density (g/cm3) Melting Point (°C) Boiling Point (°C)

molybdenum 10.28 2,623 4,639

mercury 13.53 -39 357

hafnium 13.31 2,233 4,603

lead 11.34 327 1,749

A.

molybdenum

B.

mercury

C.

hafnium

D.

lead

Answer :

The correct option is OPTION C.

(C) Hafnium

Explanation;:

We were given the mass of substance as (m) = 46.9 g

The Volume of substance as (V) = 3.5 Cm^3

But we know Density of substance.= Mass/it's Volume

Then Density=46.9/3.5

=13.4g/Cm^3

From the questionthe given substance is solid at room temperature, and let us take Mercury as an example , Mercury is liquid at room temperature. ThenMercury cannot be the answer.

Base on the determined density which is 13.4 and the density of Hafnium also is 13.31 g/cm3 and it is solid at room temperature. Therefore, Hafnium is the only likely element here.

Complete Question:

In ∆ABC, if sin A = 4/5 and tan A = 4/3, then what is cos A?

Answer:

[tex]cos A= \frac{3}{5}[/tex]

Explanation:

Given

[tex]sin A = 4/5[/tex]

[tex]tan A = 4/3[/tex]

Required

[tex]cos A[/tex]

In trigonometry;

[tex]tanA = \frac{sinA}{cosA}[/tex]

Multiply both sides by cosA

[tex]cos A * tanA = \frac{sinA}{cosA} * cos A[/tex]

[tex]cos A * tanA = sinA[/tex]

Divide both sides by tanA

[tex]\frac{cos A * tanA}{tanA} = \frac{sinA}{tanA}[/tex]

[tex]cos A= \frac{sinA}{tanA}[/tex]

Substitute values for sinA and tanA

[tex]cos A= \frac{4/5}{4/3}[/tex]

[tex]cos A= \frac{4}{5} / \frac{4}{3}[/tex]

[tex]cos A= \frac{4}{5} * \frac{3}{4}[/tex]

[tex]cos A= \frac{4 * 3}{5 * 4}[/tex]

[tex]cos A= \frac{3}{5}[/tex]

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:

C. Experiments test the scientists' ideas.

Explanation:

Experiments test the scientists' ideas. Therefore, the correct option is C.

By testing ideas and hypotheses, experiments are an essential part of the scientific method and aid scientists' understanding of the world. Science uses regulated procedures to detect particular phenomena, track results, and collect data. These studies give researchers a chance to investigate cause-and-effect relationships, detect patterns, and draw conclusions based on the data. Scientists can test their ideas, theories, and predictions by systematically adjusting various factors to see whether experimental results confirm or disprove them.

Therefore, the correct option is C.

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Answer:

in the fermentati0n process glucose [C6H12O6]c of food is converted into ethanol [ethyl alchol, C2H5OH] and Co2 by yeast cell .In this process yeast cell produce in vertase and zymase enzyme which convert glucose into alcohol .

i.e. c6H12O6========> C2H5OH+Co2+energy

Answer:

Explanation:

given

volume=1.85 d m^3

T=27 degree C=27+273 k=300 k

P=750 mmHg

mass of zinc=?

we know that PV=nRT

n=m/M

PV=mRT/M

M for zinc=65.4

PVM=mRT

m=PVM/RT

m=750*1.85*65.4/0.0821*300

m=90742.5/24.63

m=3684

hope this will help u

Answer:

pcl3 is the empirical formula of the compound

Answer:

it means air pollution Environment. The chemicals and nutrients found in fertilizers, while beneficial for agricultural crops, can be lethal in high doses for fish, birds and other wildlife. Pesticides, designed to kill pests chemically, are also dangerous when leached into soil or groundwater supplies.

Answer:

See explanation

Explanation:

Cu- 28.4/63.5, Br- 71.6/80

Cu- 0.447/0.447, Br- 0.895/0.447

Cu- 1, Br - 2

Empirical formula = CuBr2

b)

K- 39.0/39, C-12.0/12, H- 1.01/1, O- 47.9/16

K= 1, C-1, H- 1. O-3

Empirical formula= KHCO3

c)

Ag- 77.3/108, P-7.4/31, O-15.3/16

Ag-0.716/0.239, P- 0.239/0.239, O-0.956/0.239

Ag-3, P-1, O-4

Empirical formula= Ag3PO4

d)

H-0.57/1, I- 72.1/127, O-27.3/16

H- 0.57/0.57, I- 0.57/0.57, O-1.71/0.57

H-1, I-1, O- 3

Empirical formula= HIO3

Answer:

0.8833 mole of C3H8

Explanation:

Given:

Mass of C₃H₈ (Propane) = 38.95 gram

Computation:

Molar mass of C = 12.01

Molar mass of H = 1.008

Molar mass of C₃H₈ (Propane) = 3(12.01) + 8(1.008)

Molar mass of C₃H₈ (Propane) = 36.03 + 8.064

Molar mass of C₃H₈ (Propane) = 44.094

Number of mol in 38.95 gram Propane = Mass / Molar mass

Number of mol in 38.95 gram Propane = 38.95 / 44.094

Number of mol in 38.95 gram Propane = 0.88334

Answer:

Use the Periodic Table to find molar masses.

Propane (C3H8), a common fuel, reacts with oxygen to form carbon dioxide and water according to the equation below:

C3H8 + 5O2 → 3CO2 + 4H2O

If a propane heater burns 38.95 g C3H8, it consumes

38.95 mol C3H8.

0.8830 mol C3H8.

1 mol C3H8.

44.10 mol C3H8.

Part 2

How many moles of oxygen are required to produce 37.15 g CO2?

37.15 g CO2 = 1.407 mol O2

Part 3

What mass of propane is necessary to react with the amount of oxygen calculated in the previous question?

12.41   g C3H8    

Answer:

The SI system : The international system of units.

It is a scientific method of expressing the magnitudes or quantities of important natural phenomena.

Benefits of SI system

Answer:

waaaaaaaaaaqwwwwwwwwwwww

Answer:

Answer:

Ver las respuestas abajo.

Explanation:

Este problema se puede resolver conociendo la relacion entre horas y minutos, sabemos que:

1 hora [h] → 60 minutos [min]

De esta manera:

2 [min] = 2/60 = 0.033 [h]

15 [min] = 15/60 = 0.25 [h]

30 [min] = 30/60 = 0.5 [h]

10 [min] = 10/60 = 0.166 [h]

6 [min] = 6/60 = 0.1 [h]

20 [min] = 20/60 = 0.33 [h]

5 [min] = 5/60 = 0.0833 [h]

Answer:

CNa203

Explanation:

thats is method in the picture send

Answer:

I guess eraser is better than bread crumbs

Erasers would be better than white bread or crumbs to erase the pencil marks because they would not leave any food marks on the paper and using bread crumbs.

An eraser is an object of stationary which is used to remove pencil marks from the paper. It is used during writing, when we write something wrong, we could erase or remove the writing from the paper. It is very useful for small children because they usually make mistakes while studying.

Erasers are made from the milk of rubber plants. The milk is collected from the plants, and then it is mixed with chemicals and set down, and then cut into pieces.

Thus, Erasers would be preferable to utilizing bread crumbs or white bread because they would not leave any food stains on the paper after erasing the pencil markings.

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Answer:

using a more concentrated potassium hydroxide

Explanation:

The option that would likely increase the rate of reaction would be to use a more concentrated potassium hydroxide.

The concentration of reactants is one of the factors that affect the rate of reaction. The more the concentration of the reactants, the faster the rate of reaction.

Granted that there are enough of the other reactants, increasing the concentration of one of the reactants will lead to an increased rate of reaction.

Hence, using a more concentrated potassium hydroxide which happens to be one of the reactants would likely increase the rate of reaction.

Answer:

using a more concentrated potassium hydroxide

Explanation:

Answer:

Ingredients OR tenderising

Explanation:

Answer:

Physical properties are defined as the properties which can be observed without changing its chemical composition.

For example: color, volume, and molecular weight.

Chemical properties are defined as the properties which can be observed only after changing chemical identity of the substance.

For example: reactivity, toxicity, and flammability.

The fundamental differences between physical and chemical properties are as follows:

Chemical properties are related to chemical bonds of the substance while physical properties are not.

In chemical properties, chemical identity of substance changes while physical properties do not have any change.

Chemical properties predict the reaction of substance while physical properties only describe the appearance of the substance.

Explanation:

Answer:

A measurable property that can be observed typically and explains any matter or organism's appearance and physical behavior is called a physical property. Examples of physical properties are appearance, boiling point, freezing point, melting point, colors, odor, mass, density, solubility. Properties that are only observed during a reaction or change in the composition of a matter is called a chemical property. These properties describe the internal part of anything and explain how it behaves when reacted with other chemical substances. Examples are enthalpy, entropy, reactivity, flammability, oxidation state, acidity, basicity. Some physical properties are reversible or sometimes irreversible. Like the change of states of matter is reversible, and the growth of an organism is irreversible. The same thing with the chemical properties. There are reversible chemical reactions(formation of ammonium chloride) and irreversible chemical reactions. (burning of a chemical substance). After knowing all about these properties, the most fundamental difference is that the physical properties can be measured without any chemical change in them. But a chemical property is measurable when the substance goes through a chemical reaction.

Explanation: