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2 years ago

12

Which of these are physical changes in matter check all that apply .

2 answers:

sergeinik [125]2 years ago

7 0

What answers are there? you didn't add them.

physical change and chemical change.

physical change affects a substance's physical properties, and a chemical change affects its chemical properties.

Orlov [11]2 years ago

6 0

Answer:

boiling water

sharpening a pencil

freezing water

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The ph of a solution for which [OH]= 1.0 x 10^-4 is?<br><br> A 10<br> B 14<br> C 11<br> D 9<br> E 7

zhenek [66]

To find pH, use the following formula ---> pH= - log [H+]

so first we need to calculate the [H+] concentration using the OH concentration. to do this, we need to use this formula--> 1.0x10-14= [H+] X [OH-], so we solve for H+ and plug in

[H+]= 1.0X10-14/[OH-]---> 1.0 x 10-14/ 1.0 x 10-4= 1.0 x 10-10

now that we have the H+ concentration, we can solve of pH

pH= -log (1.0x10-10)= 10

answer is A

8 0

3 years ago

Calculate the pH of a buffer prepared by mixing 20.0 mL of 0.10 M acetic acid and 55.0 mL of 0.10 M sodium acetate

MatroZZZ [7]

Answer:

Calculate the pH of a buffer prepared by mixing 30.0 mL of 0.10 M acetic acid and 40.0 mL of 0.10 M sodium acetate.

3 0

3 years ago

HRISTINA HERRERA: Attempt 1

Lunna [17]

Answer:

7.5 g of hydrogen gas reacts with 50.0 g oxygen gas to form 57.5 g of water.

Explanation:

Here we have the check if the mass of the reactants is equal to the mass of the products.

Reactants

$7.5+50=57.5\ \text{g}$

Products

$57.5\ \text{g}$

The data is consistent with the law of conservation of matter.

Reactants

$50+243=293\ \text{g}$

Products

$206+97=303\ \text{g}$

The data is not consistent with the law of conservation of matter.

Reactant

$17.7+34.7=52.4\ \text{g}$

Products

$62.4\ \text{g}$

The data is not consistent with the law of conservation of matter.

Only the first data is consistent with the law of conservation of matter.

8 0

2 years ago

What is the answer to 4x - 16

andrezito [222]

It simply equals 4x-16.......
the expression is in lowest terms, so you can’t do anything else

4 0

3 years ago

Read 2 more answers

A brick has a mass of 4.0 kg and the Earth has a mass of 6.0 × 1027 g. Use this information to answer the questions below. Be su

Vedmedyk [2.9K]

Answer:

a) $2.4\times 10^{24} kg$ is the mass of 1 mole of bricks.

b) $2.5\times 10^3$ moles of bricks have a mass equal to the mass of the Earth.

Explanation:

a) Mass of brick = 4.0 kg

1 mole = $N_A=6.022\times 10^{23}$ particles/ atoms/molecules

Mass of $N_A$ bricks :

$=6.022\times 10^{23}\times 4.0 kg=2.4088\times 10^{24} kg\approx 2.4\times 10^{24} kg$

$2.4\times 10^{24} kg$ is the mass of 1 mole of bricks.

b)

Mass of the Earth = M = $6.0\times 10^{27} kg$

Mass of 1 mole of brick = m= $2.4\times 10^{24} kg$

Let the moles of brick with equal mass of the Earth be x.

$m\times x=M$

$x=\frac{M}{m}=\frac{6.0\times 10^{27}kg}{2.4\times 10^{24} kg}=2.5\times 10^3$

$2.5\times 10^3$ moles of bricks have a mass equal to the mass of the Earth.

7 0

3 years ago