1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
Gnom [1K]
3 years ago
10

which best describes an element? - a pure substance - a type of a mixture - a pure compound - an impure substance

Chemistry
2 answers:
Nikitich [7]3 years ago
7 0
An element is a pure substance which means it cannot be broken down by any means.
STatiana [176]3 years ago
4 0

Answer:

A pure substance

Explanation:

An element is a pure substance.

It is only made up of atoms of the same type.

You might be interested in
Question:
den301095 [7]

Answer: I think it’s 4

Explanation:

8 0
3 years ago
Write a balanced nuclear equation for the formation of 28 Si 14 from beta-minus emission.
Fantom [35]

Answer:

Phosphorus-28 undergoes beta-minus decay to produce

  • an electron,
  • a Silicon-28 nuclei, and
  • an electron antineutrino.

\rm ^{28}_{13} Al \to ^{28}_{14} Si + ^{\phantom{-}0}_{-1}e + \bar{\mathnormal{v}}_{\rm e}

Explanation:

In simple words, when a nucleus undergoes beta-minus decay, a neutron is converted to a proton. An electron and an electron antineutrino will be released.

\rm ^{1}_{0}n^{0} \to ^{1}_{1}p^{+} + ^{\phantom{-}0}_{-1}e^{-} + \bar{\mathnormal{v}}_{\rm e}.

One way to tell whether a neutron is converted to a proton, but not vice versa, is to check the sum charges on the two sides of this equation.

  • Left-hand side: 0. Neutron is neutral.
  • Right-hand side: 1 + (-1) = 0. Each proton carries a charge of +1. Each electron (beta-minus particle) carries a charge of -1. Antineutrinos are neutral.

The charges on the two sides of this equation is the same. Hence this nuclear equation is possible (but not necessarily correct; however, if the proton and the neutron are in the wrong place the charge won't even be the same.)

Since the mass number of a proton and a neutron are both 1, the overall mass number of the atom will stay the same.

The atomic number is the number of protons in each atom. That number determines the symbol and the chemical properties of the atom. When one neutron in an atom is converted to a proton, the atomic number of the atom will increase by 1.

The atomic number of the daughter nucleus, silicon, is 14. It takes a parent nucleus with atomic number 14 - 1 = 13 to produce a silicon atom. Refer to a modern periodic table. Atomic number 13 corresponds to the element aluminum.

Also, the mass number of the daughter nucleus is 28. Since the mass number would stay the same in a beta decay, the mass number of the parent nucleus would also be 28. In other words, it takes an aluminum-28 atom to undergo beta-decay to produce a silicon-28 atom.

Complete the other details (electron and electron antineutrino) to obtain the equation

\rm ^{28}_{13} Al \to ^{28}_{14} Si + ^{\phantom{-}0}_{-1}e + \bar{\mathnormal{v}}_{\rm e}.

6 0
3 years ago
Oblicz masę tlenu, wiedząc, że wypełnia on pomieszczenie o rozmiarach 2m x 3.5m x 3m. Gęstość tlenu wynosi 1,249kg/m3 .
Tanzania [10]

Analiza Z drugiej zasady Newtona przyłożona siła wynosi 1 N F = ma = m (6 g) = (90 kg) (6x9,81 m / s) 5297 N I kg m / s?

8 0
2 years ago
Why is a molecule of CO2 nonpolar even though the bonds between the carbon atom and the oxygen atoms are polar?
schepotkina [342]
The correct answer is option 1. Carbon dioxide is nonpolar because the shape of the molecule  is symmetrical. It is a linear molecule where the oxygen atoms are symmetrical on each end. CO2 molecule do not have a region of unequal sharing.
7 0
2 years ago
A sample of krypton gas with a volume of 10.00 L has a temp of 303 K and exerts
marshall27 [118]

<u>Answer:</u> The final volume will be 14.85 L.

<u>Explanation:</u>

To calculate the final volume when temperature increases, we use Charles' Law.

This law states that volume is directly proportional to the temperature of the gas if number of moles and pressure remains constant.

V\propto T\\\\\frac{V_1}{T_1}=\frac{V_2}{T_2}

where,

V_1\text{ and }T_1 = Initial volume and temperature

V_2\text{ and }T_2 = Final volume and temperature

We are given:

V_1=10L\\&#10;T_1=303K\\&#10;V_2=?L\\&#10;T_2=450K

Putting values in above equation, we get:

\frac{10L}{303K}=\frac{V_2}{450K}

V_2=14.85L

Hence, the final volume of the gas is 14.85L

7 0
3 years ago
Other questions:
  • A sample of sulfur hexafluoride gas occupies a volume of 5.10 L at 198 ºC. Assuming that the pressure remains constant, what tem
    14·1 answer
  • The two naturally occurring isotopes of antimony, 121Sb (57.21 percent) and 123Sb (42.79 percent), have masses of 120.904 and 12
    11·1 answer
  • How many electrons can the n=4 shell hold?<br> a. 8b.16c.32d.64?
    11·2 answers
  • If radiation normally travels at the speed of light, why does it take longer than 100,000 years for energy from thermonuclear re
    13·1 answer
  • What is the value of the equilibrium constant at 25 oC for the reaction between the pair: Ag(s) and Ni2+(aq) to give Ni(s) and A
    9·1 answer
  • BRAINLIESTT ASAP! PLEASE HELP ME :)<br><br> Compare stored mechanical energy and mechanical energy.
    12·1 answer
  • Answer these please! 23 points!
    15·1 answer
  • Select the correct answer.
    6·2 answers
  • The diagram shows an early model of the atom. It was suggested by JJ Thompon. The atom was thought to be positively charged
    10·2 answers
  • Which of the following measurements have four significant figures? Select all that apply. A.1,001g B.120.0mL C.0.0007cm D.5,000s
    9·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!