Ask question

Ask question

All categories

3 years ago

5

Fill in the blank. A ___ is a substance that cannot be separated into simpler substances by physical or mechanical methods such

as filtering, boiling, or sifting

2 answers:

Ganezh [65]3 years ago

8 0

An element cannot be broken down any further. Elements can be found on the periodic table

PolarNik [594]3 years ago

8 0

I think it's a pure substance

You might be interested in

Consider the reaction between acetylene, c2h2, and oxygen in a welding torch: 2c2h2(g) + 5o2(g) → 4co2(g) + 2h2o(g) if 5.4 moles

fredd [130]

<span> 2C2H2(g) + 5O2(g) → 4CO2(g) + 2H2O(g)
from the reaction 2 mol 4 mol
from the problem 5.4 mol 10.8 mol

M(CO2) = 12.0 +2*16.0 = 44.0 g/mol
10.8 mol CO2 * 44.0 g CO2/1 mol CO2 = 475.2 g CO2 </span>≈480 = 4.8 * 10² g
Answer is C. 4.8*10² g.

4 0

3 years ago

Read 2 more answers

Carbon-14 has a half-life of 5720 years and this is a fast-order reaction. If a piece of wood has converted 75 % of the carbon-1

Nana76 [90]

Answer:

11445.8years

Explanation:

Half-life of carbon-14 = 5720 years

First we have to calculate the rate constant, we use the formula :

7 0

3 years ago

It takes 281.7 kJ of energy to remove 1 mole of electrons from the atoms on the surface of lithium metal. If lithium metal is ir

Alex17521 [72]

Answer:

The maximum kinetic energy of electron is = 2.93 × $10^{-19}$ Joule

Explanation:

We know that total energy

$E = \frac{hc}{\lambda}$ ------------ (1)

Here h = plank's constant = 6.62 × $10^{-34}$ J s

c = speed of light = 3 × $10^{8}$ $\frac{m}{s}$

$\lambda$ = 261 nm = 261 × $10^{-9}$ m

Put all these values in equation (1) we get

E = 7.6 × $10^{-19}$ J

We know that

Total energy = Energy to remove an electron + K.E of electron

Energy to remove an electron = $\frac{281.7 (1000)}{(6.023)10^{23} }$

Energy to remove an electron = 4.67 × $10^{-19}$ J

K.E of electron = Total energy - Energy to remove an electron

K.E of electron = 7.6 × $10^{-19}$ - 4.67 × $10^{-19}$

K.E of electron = 2.93 × $10^{-19}$ Joule

Therefore the maximum kinetic energy of electron is = 2.93 × $10^{-19}$ Joule

3 0

3 years ago

What events caused the formation of most islands in the South Pacific?

WINSTONCH [101]

D. Volcanoes formed most of them through eruption.

7 0

3 years ago

Matter and energy are

Wewaii [24]

When energy transforms into mass, the amount of energy does not remain the same. When mass transforms into energy, the amount of energy also does not remain the same. However, the amount of matter and energy remains the same. ... You would weigh much less on the Moon because it is only about one-sixth the mass of Earth. So the answer is D

3 0

3 years ago