True or false? Salt water takes a shorter time to boil than regular water. Send help!!!!

Explain examples of a physical and chemical change of matter

monitta

HEY DEAR..

PHYSICAL CHANGE

Those Changes in which no new substances are formed are called physical changes. it is a temporary changes which can be reversed easily to form the original substance.

Example:- Melting of ice , Making a solution, Glowing of an electric bulb , freezing of water etc.

CHEMICAL CHANGE

Those changes in which new substances are formed are called chemical changes. it means it is permanent changes which are usually irreversible.

Example:- Burning of charcoal, fuels and cutting of trees, even digestion of food is in chemical change.

HOPE ITS HELPFULLL

BE BRAINLY.

6 0

3 years ago

HELP please! Which of these describes how heat is transferred by conduction

VLD [36.1K]

D. Air molecules touch the warm ground, heating them up

3 0

3 years ago

Calculate the change in energy when 75.0 grams of water drops from 31.0C to 21.6.

zysi [14]

Answer: Step 1: Calculate qsur (the surrounding is

usually the water)

qsur = ? J

m = 75.0 g water

c = 4.184 J/g

oC

ΔT = (Tfinal- Tinitial)= (21.6 – 31.0) = -9.4 oC

qsur = m · c · (ΔT)

qsur = (75.0g) (4.184 J/g

oC) (-9.4 oC)

qsur = - 2949.72 J

First, using the information we know that we

must solve for qsur, which is the water. We know

the mass for water, 75.0g, the specific heat of

the water, 4.184 j/g

o

c, and the change in

temperature, 21.6-31.0 = -9.4 oC. Plugging it

into the equation, we solve for qsur.

Step 2: Calculate qsys qsys = - (qsur)

qsys = - (- 2949.72 J)

qsys = + 2949.72

In this case, the qsur is negative, which means

that the water lost energy. Where did it go? It

went to the system. Thus, the energy of the

system is negative, opposite, the energy of the

surrounding.

Step 3: Calculate moles of the substance

that is the system

Given: 12.8 g KCl

Mol system = (g system given)

(molar mass of system)

Mol system = (12.8 g KCl)

(39.10g + 35.45g)

Mol system = 12.8 g KCl

74.55 g

Mol system = 0.172

Here, we solve for the mol in the system by

using the molar mass of the material in the

system.

Step 4: Calculate ΔH ΔH = q sys .

Mol system

ΔH= + 2949.72 J

0.172 mol

ΔH= +17179.81 J/mol or +1.72 x 104

J/mol

i hope this helps

5 0

3 years ago

Read 2 more answers

If 42 grams of carbon and 52 grams of oxygen are used, how many grams of CO2 will be produced (Hint: find the

zavuch27 [327]

Answer:

71.5g

Explanation:

The reaction equation is given as:

C + O₂ → CO₂

Mass of C = 42g

Mass of O₂ = 52g

Unknown:

Mass of CO₂ produced = ?

Solution

Now to solve this problem, we have to find limiting reactant which is the one given in short supply in this reaction.

The extent of the reaction is controlled by this reactant.

Find the number of moles of the given species;

Number of moles = $\frac{mass}{molar mass}$

Number of moles of C = $\frac{42}{12}$ = 3.5mol

Number of moles of O₂ = $\frac{52}{32}$ = 1.63mol

Now;

From the balanced reaction equation;

1 mole of C reacted with 1 mole of O₂

We see that C is in excess and O₂ is the limiting reactant.

1 mole of O₂ will produce 1 mole of CO₂

So; 1.63mole of O₂ will produce 1.63 mole of CO₂

Mass of CO₂ = number of moles x molar mass

Molar mass of CO₂ = 44g/mol

Mass of CO₂ = 1.63 x 44 = 71.5g

8 0

3 years ago

It is the kind of interaction in which both organisms benefit from each other. *

MArishka [77]

Answer:

Mutualism

Explanation:

4 0

3 years ago