All categories

3 years ago

Define chemical change and give an example

2 answers:

7 0

Chemical changes are the chemical properties associated with a specific matter.

Examples include toxicity, reactivity, stability, flammability, etc.

Brilliant_brown [7]3 years ago

4 0

Definition-A formation of new chemical substances.
Example- Sugar undergoes a chemical change when it is cooked to make caramel. :3

Hope I helped! Sorry if it's bad.

You might be interested in

Concentrated hydrogen peroxide solutions are explosively decomposed by traces of transition metal ions (such as Mn or Fe): 2H2O2

zalisa [80]

Answer:

23.0733 L

Explanation:

The mass of hydrogen peroxide present in 125 g of 50% of hydrogen peroxide solution:

$Mass=\frac {50}{100}\times 125\ g$

Mass = 62.5 g

Molar mass of $H_2O_2$ = 34 g/mol

The formula for the calculation of moles is shown below:

$moles = \frac{Mass\ taken}{Molar\ mass}$

Thus, moles are:

$moles= \frac{62.5\ g}{34\ g/mol}$

$moles= 1.8382\ mol$

Consider the given reaction as:

$2H_2O_2_{(aq)}\rightarrow2H_2O_{(l)}+O_2_{(g)}$

2 moles of hydrogen peroxide decomposes to give 1 mole of oxygen gas.

Also,

1 mole of hydrogen peroxide decomposes to give 1/2 mole of oxygen gas.

So,

1.8382 moles of hydrogen peroxide decomposes to give $\frac {1}{2}\times 1.8382 mole of oxygen gas. Moles of oxygen gas produced = 0.9191 molGiven: Pressure = 746 torr
The conversion of P(torr) to P(atm) is shown below:
[tex]P(torr)=\frac {1}{760}\times P(atm)$

So,

Pressure = 746 / 760 atm = 0.9816 atm

Temperature = 27 °C

The conversion of T( °C) to T(K) is shown below:

T(K) = T( °C) + 273.15

So,

T₁ = (27 + 273.15) K = 300.15 K

Using ideal gas equation as:

PV=nRT

where,

P is the pressure

V is the volume

n is the number of moles

T is the temperature

R is Gas constant having value = 0.0821 L.atm/K.mol

Applying the equation as:

0.9816 atm × V = 0.9191 mol × 0.0821 L.atm/K.mol × 300.15 K

⇒V = 23.0733 L

8 0

2 years ago

6th grade help me pleaseeeee

Vesnalui [34]

Answer:

the answer would be A. cells

Explanation:

just trust me Im a 8th grader and I did that before

7 0

3 years ago

Which statement describes an open circuit? The circuit is incomplete and broken, and the lights in the circuit shine. The circui

SVEN [57.7K]

Answer:

the third option

Explanation:

The circuit is incomplete and broken, and the lights in the circuit do not shine.

An open circuit means an incomplete circuit.

The first option is wrong since the lights do not shine in an open circuit.

The second option is wrong since an open circuit is incomplete.

The fourth option is also wrong since an open circuit is broken or incomplete.

∴ The third option is correct.

8 0

3 years ago

Read 2 more answers

How many atoms are in 3.2 pg of Ca? The molar mass of Ca is 40.08 g/mol.

anyanavicka [17]

Answer:

4.81×10¹⁰ atoms.

Explanation:

We'll begin by converting 3.2 pg to Ca to grams (g). This can be obtained as follow:

1 pg = 1×10¯¹² g

Therefore,

3.2 pg = 3.2 pg × 1×10¯¹² g / 1 pg

3.2 pg = 3.2×10¯¹² g

Therefore, 3.2 pg is equivalent to 3.2×10¯¹² g

Next, we shall determine the number of mole in 3.2×10¯¹² g of Ca. This can be obtained as follow:

Mass of Ca = 3.2×10¯¹² g

Molar mass of Ca = 40.08 g/mol

Mole of ca=.?

Mole = mass /molar mass

Mole of Ca = 3.2×10¯¹² / 40.08

Mole of Ca = 7.98×10¯¹⁴ mole.

Finally, we shall determine the number of atoms present in 7.98×10¯¹⁴ mole of Ca. This can be obtained as illustrated below:

From Avogadro's hypothesis,

1 mole of Ca contains 6.02×10²³ atoms.

Therefore, 7.98×10¯¹⁴ mole of Ca will contain = 7.98×10¯¹⁴ × 6.02×10²³ = 4.81×10¹⁰ atoms.

Therefore, 3.2 pg of Ca contains 4.81×10¹⁰ atoms.

7 0

3 years ago

A) 4 B) 3 C) 2 D) 1 HELP PLEASEEEEEEEEEE

SVETLANKA909090 [29]

The peaks are there where the centre of the concentric circles lie. (Not circles exactly)

You can count a total 4 of them.

So there are a total of 4 peaks

See the attachment. I have marked them with a cross.

8 0

3 years ago