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2 years ago

PLEASE HELP!!! WILL MARK BRAINLIEST!!!!!

Chemistry

1 answer:

Hoochie [10]2 years ago

4 0

Answer: 1) D. 2) C. 3) A. 4) C. 5) B. 6) B. 7) A. 8) D. 9) A. 10) C. 11) B.

Explanation: I really hope this helps

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Matter can be a compound and a _______.

ratelena [41]

Answer:

Mixtures

Explanation:

Matter can be classified as a compound and a mixture.

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3 years ago

Chemistry! help! please!

VARVARA [1.3K]

It would be 187 75 Re since 76 - 1 is 75 and number 2 would be beta particle and a positron.

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3 years ago

Read 2 more answers

What is the kinetic energy in kJ of 1 mole of water molecules (mass=18) if the average velocity is 590 m/s (1300 mph)

zubka84 [21]

Answer:

= 3132.9 Joules

Explanation:

Kinetic energy is the energy possessed by a body when in motion.
Kinetic energy is calculated by the formula; K.E = 1/2 mV², where m is the mass of the body or object, and V is the velocity.

Therefore kinetic energy depends on the mass and the velocity of the body or the object in motion.

In this case;

Kinetic energy = 0.5 × 0.018 kg × 590²

<u>= 3132.9 Joules</u>

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3 years ago

How many atoms are in 25.00 g of B.

iren2701 [21]

Answer:

$\boxed {\boxed {\sf 1.393 *10^{24} \ atoms \ B}}$

Explanation:

<u>1. Convert Grams to Moles</u>

Use the molar mass (found on the Periodic Table) to convert from grams to moles.

Boron (B): 10.81 g/mol

Use this value as a ratio.

$\frac {10.81 \ g \ B }{1 \ mol \ B}$

Multiply by the given number of grams.

$25.00 \ g \ B *\frac {10.81 \ g \ B }{1 \ mol \ B}$

Flip the ratio so the grams of boron cancel out.

$25.00 \ g \ B *\frac {1 \ mol \ B }{10.81 \ g \ B}$

$25.00 *\frac {1 \ mol \ B }{10.81 }$

$\frac {25.00 \ mol \ B }{10.81 }=2.312673451 \ mol \ B$

<u>2. Convert Moles to Atoms</u>

We use Avogadro's Number, 6.02*10²³: the number of particles (atoms, molecules, etc.) in 1 mole of a substance. In this case, the particles are atoms of boron.

$\frac {6.02*10^{23} \ atoms \ B} {1 \ mol \ B}$

Multiply by the number of moles we calculated.

$2.312673451 \ mol \ B *\frac {6.02*10^{23} \ atoms \ B} {1 \ mol \ B}$

The moles of boron cancel.

$2.312673451 *\frac {6.02*10^{23} \ atoms \ B} {1 }$

$2.312673451 *6.02*10^{23} \ atoms \ B} =1.39269195*10^{24} \ atoms \ B$

The original value of grams has 4 significant figures, so our answer should have the same. For the number we calculated, that is the thousandth place.

$1.392\underline69195*10^{24} \ atoms \ B$

The 6 tells us to round the 2 to a 3.

$1.393 *10^{24} \ atoms \ B$

25.00 grams of boron is equal to 1.393*10²⁴ atoms.

6 0

3 years ago

Calculate the number of atoms in 0.25 moles of manganese?

White raven [17]

<h3>Answer:</h3>

1.5 × 10²³ atoms Mn

<h3>General Formulas and Concepts:</h3>

<u>Math</u>

<u>Pre-Algebra</u>

Order of Operations: BPEMDAS

Brackets
Parenthesis
Exponents
Multiplication
Division
Addition
Subtraction

Left to Right

<u>Chemistry</u>

<u>Atomic Structure</u>

Using Dimensional Analysis
Avogadro's Number - 6.022 × 10²³ atoms, molecules, formula units, etc.

<h3>Explanation:</h3>

<u>Step 1: Define</u>

0.25 mol Mn

<u>Step 2: Identify Conversions</u>

Avogadro's Number

<u>Step 3: Convert</u>

Set up: $\displaystyle 0.25 \ mol \ Mn(\frac{6.022 \cdot 10^{23} \ atoms \ Mn}{1 \ mol \ Mn})$
Multiply: $\displaystyle 1.5055 \cdot 10^{23} \ atoms \ Mn$

<u>Step 4: Check</u>

<em>Follow sig fig rules and round. We are given 2 sig figs.</em>

1.5055 × 10²³ atoms Mn ≈ 1.5 × 10²³ atoms Mn

3 0

3 years ago