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2 years ago

15

Compare the type of change that occurs when a match is burnt and when a liquid starts boiling. Use complete sentences to justify

the type of change that occurs. (10 points)

1 answer:

Alexandra [31]2 years ago

8 0

Answer: When a match is burnt, the fire catches

Explanation: because

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Metals have high melting and boiling points and are often shiny and silvery. Which of the blocks are metals?

DanielleElmas [232]

Answer:

S and p blocks elements are considered metals while d-block elements are considered transition metals.

Explanation:

s-block consist of lithium, sodium, potassium, rubidium, cesium and francium metals.

All are these called alkali metals.

These metals have one valance electron.

These metals are soft and having low density.

They easily lose their one valance electron and form cation with +1 charge.

They have low melting points.

P- block elements includes beryllium, magnesium, calcium, strontium, barium, radium metals.

They are called alkaline earth metals.

All are these have two valance electrons.

They easily lose their valance electrons and form cation with charge of +2.

These metals are also very soft.

They form salt with halogens.

They are also very reactive metals.

8 0

3 years ago

Suppose a 10.0 mL sample of an unknown

mote1985 [20]

The concentration of HCl is equal to 2.54mol/L.

<h3>Mole calculation</h3>

To solve this question, one must use the molarity calculation, which corresponds to the following expression:

$M = \frac{mol}{v}$

Thus, to find the molarity of the sample, the following calculations must be performed:

$V_f = 10ml + 625ml = > 635ml$

$\frac{0.004mol}{xmol} =\frac{1000ml}{635ml}$

$x = 0.00254 mol$

So, 0.00254 moles were added per 10ml, so we can do:

$\frac{0.00254mol}{xmol}= \frac{10ml}{1000ml} \\x = 2.54mol/L$

So, the concentration of HCl is equal to 2.54mol/L.

Learn more about mole calculation in: brainly.com/question/2845237

6 0

2 years ago

The decay of which radioisotope can be used to estimate the age of the fossilized remains of an insect?

Dmitriy789 [7]

(4) C-14 Carbon is found in all living organisms.

3 0

3 years ago

Read 2 more answers

CAN SOMEONE HELP ME!!!

NISA [10]

Answer:

I think D

Explanation:

4 0

3 years ago

Read 2 more answers

If a proton and an electron are released when they are 5.50×10−10 mm apart (typical atomic distances), find the initial accelera

Vlada [557]

Answer: The initial acceleration of the proton = (4.56 × 10^23) m/s2

The initial acceleration of the electron = (8.36 × 10^26) m/s2

Explanation: The force of attraction between the proton and electron can be computed using the statements of Coulomb's law which state that the force of attraction between two charged particles is directly proportional to the product of the two charges and inversely proportional to the square of their distances apart.

F = (Kq1q2)/(r^2) where K = (9 × (10^9) Nm(C^-2))

But q1 is the charge on a proton = (1.6 × (10^-19)) C

q2 is charge on an electron = -(1.6 × (10^-19)) C

r = (5.50 × (10^-10))mm = (5.50 × (10^-13))m

Computing all that, F = 0.0007616529 N = (7.62 × 10^-4) N

But the force of attraction is converted to that required for motion when they're released.

F = ma.

For proton, m = (1.67 × 10^-27) kg

a = F/m = 0.000762/(1.67 × 10^-27) = (4.56 × 10^23) m/s2

For electron, m = (9.11 × 10^-31) kg

a = F/m = 0.000762/(9.11 × 10^-31) = (8.36 × 10^26) m/s2

QED!

7 0

3 years ago