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MariettaO [177]

3 years ago

15

Firewood burns and ashes remain is it a chemical or physical change?

2 answers:

dexar [7]3 years ago

7 0

Respuesta: físico

Explanation:El papel, la ceniza y el humo son sustancias diferentes. CLASES DE CAMBIOS QUÍMICOS: ... En la combustión la materia arde y se forman otras sustancias, como ceniza, vapor de agua y dióxido de carbono. Por ejemplo, se produce una combustión cuando arde la madera

erastova [34]3 years ago

4 0

It is a physical change because you can not put it back like it was

You might be interested in

What is the change in density if a sample goes from 3.21 g/L to 5.43 g/mL?

Step2247 [10]

Answer:

$\Delta \rho =2.22 g/mL$

Explanation:

Hello,

In this case, since a change in science is widely known to be considered as a subtraction between the the final and initial values of two measured variables and is represented via Δ, here the final density is 5.43 g/mL and the initial one was 3.21 g/mL, therefore, the change in density is:

$\Delta \rho=\rho _f-\rho _i\\ \\\Delta \rho=5.43g/mL-3.21g/mL\\\\\Delta \rho =2.22 g/mL$

Best regards.

3 0

3 years ago

How many grams of Cabr2 would be needed to create 450 mL of a 2.00 M solution?

Yanka [14]

Answer:

Mass = 179.9 g

Explanation:

Given data:

Volume of solution = 450 mL

Molarity of solution = 2.00 M

Mass in gram required = ?

Solution:

Volume of solution = 450 mL× 1 L / 1000 mL = 0.45 L

Molarity = number of moles of solute/ Volume of solution in L

2.00 M = number of moles of solute / 0.45 L

Number of moles of solute = 2.00 M × 0.45 L

M = mol/L

number of moles of solute = 0.9 mol

Mass of CaBr₂ in gram:

Mass = number of moles × molar mass

Mass = 0.9 mol ×199.89 g/mol

Mass = 179.9 g

6 0

3 years ago

A balloon has a volume of 1.75L at a temperature of 298K. What will be the volume of the balloon if you take it out into the win

lozanna [386]

Answer:

1.52 L

Explanation:

P1V1T2=V2P2T1

V2=V1T2/T1

Fill in with given values then solve

We can check this by knowing that V and T at constant P have a proportional relationship. Hence, this is correct.

- Hope that helped! Please let me know if you need further explanation.

7 0

2 years ago

The true absorbance for a 1.0 x 10 −5 M solution is 0.7526. If the percentage stray light for a spectrophotometer is 0.56%, calc

Korvikt [17]

Answer:

The percentage deviation is $\Delta M = 1.87$ %

Explanation:

From the question we are told that

The concentration is of the solution is $C = 1.0*10^{-5} M$

The true absorbance A = 0.7526

The percentage of transmittance due to stray light $z = 0.56$ % $=\frac{0.56}{100} = 0.0056$

Generally Absorbance is mathematically represented as

$A = -log T$

Where T is the percentage of true transmittance

Substituting value

$0.7526 = - log T$

$T = 10^{-0.7526}$

$= 0.177$

$= 17.7$ %

The Apparent absorbance is mathematically represented

$A_p = -log (T +z)$

Substituting values

$A_p = -log(0.177 + 0.0056)$

$= -log(0.1826)$

= 0.7385

The percentage by which apparent absorbance deviates from known absorbance is mathematically evaluated as

$\Delta A = \frac{A -A_p}{A} * \frac{100}{1}$

$= \frac{0.7526 - 0.7385}{0.7526} * \frac{100}{1}$

$\Delta A = 1.87$ %

Since Absorbance varies directly with concentration the percentage deviation of the apparent concentration from know concentration is

$\Delta M = 1.87$ %

6 0

3 years ago

Calcium chloride and silver nitrate react to form a precipitate of silver chloride in a solution of calcium nitrate. This is an

rewona [7]

B a Displacement reaction.

8 0

3 years ago