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2 years ago

6

Four groups of students were each asked to create table listing two elements and two compounds. Only one group’s table was corre

ct. Which group’s table is correct? [Can someone just please answer]

1 answer:

Alex_Xolod [135]2 years ago

5 0

The answer would be group 2

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Which list correctly aligns the levels of organisms from the least to the most complex? A. organ → system → tissue → cell B. tis

enyata [817]

It should be D, cells are parts, tissue is part and organ is part of a system.

6 0

2 years ago

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NeX [460]

Answer:

seriously ....,........

I don't like chemistry

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2 years ago

Neutral atoms contain equal numbers of A protons and electrons. B protons and neutrons. C electrons and neutrons. D protons, ele

Verdich [7]

<u>Answer:</u>

<u>For 1:</u> The correct answer is Option A.

<u>For 2:</u> The correct answer is Option B.

<u>For 3:</u> The correct answer is Option C.

<u>Explanation:</u>

<u>For 1:</u>

Atomic number is defined as the number of electrons or number of protons that are present in a neutral atom. It is represented as Z.

Z = Atomic number = Number of electrons = Number of protons

Mass number is defined as the sum of number of protons and number of neutrons present in an atom. It is represented as A.

A = Mass number = Number of protons + Number of neutrons

Hence, the correct answer is Option A.

<u>For 2:</u>

The isotopic representation of an atom is: $_Z^A\textrm{X}$

where,

Z = Atomic number of the atom

A = Mass number of the atom

X = Symbol of the atom

We are given:

An isotopic representation of beryllium atom: $_4^9\textrm{Be}$

Thus, the number '4' represents the atomic number of beryllium, number '9' represents the mass number of beryllium atom.

Hence, the correct answer is Option B.

<u>For 3:</u>

In CO compound:

Mass of oxygen = 16 g

Mass of carbon = 12 g

In $CO_2$ compound:

Mass of oxygen = 32 g

Mass of carbon = 12 g

Thus, the ratio of mass of oxygen in $CO_2$ and CO is:

$CO_2:CO=32:16=2:1$

Hence, the correct answer is Option C.

3 0

3 years ago

At 273 k and 1.00 x 10^-2 atm, the density of a gas is 1.24 x 10^-5 g/cm3.

bija089 [108]

Root mean square velocity is the square root of the mean of the squares of speeds of different molecules. From kinetic theory of gas, the formula of root mean square velocity=C $_{rms}$ = √ $\frac{3RT}{M}$ =√ $\frac{3PV}{M}$ =√ $\frac{3P}{d}$ , where, R= Universal gas constant, T= Absolute temperature, P= Pressure, V= Volume of gas, d= Density of gas.

Given, T=273 K, P=1.00 x 10⁻² atm, d=1.24 x 10⁻⁵ g/cm³.

(a) Using the formula $C_{rms}$ =√ $\frac{3P}{d}$ =√(3X1.00X10⁻²)/(1.24X10⁻⁵)=49.18

(b) Molar mass can be determined by using the formula $C_{rms}$ =√{3RT}{M}

49.18=√ $\frac{3X8.314X273}{M}$

49.18²=√(3X8.314X273)/M

M= $\frac{3X8.314X273}{49.18^{2} }$

M=1.67 ≅ 2

Molecular mass is 2.

(c) The gas is Helium (He) whose molecular mass is 2.

8 0

3 years ago

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Suppose you are working with a NaOH stock solution but you need a solution with a lower concentration for your experiment. Calcu

Svet_ta [14]

Answer:

$V_1=23.3~mL$

Explanation:

In this case, we have a dilution problem. We have to remember that in the dilution procedure we go from a solution with higher concentration to a solution with lesser concentration. Therefore we have to start with the dilution equation:

$C_1*V_1=C_2*V_2$

Now we can identify the variables:

$C_1=~1.475_M$

$V_1=~?$

$C_2=~0.1374_M$

$V_2=~250.0~mL$

If we plug all the values into the equation:

$1.475_M*V_1=0.1374_M*250.0~mL$

And we solve for $V_1$ :

$V_1=\frac{0.1374_M*250.0~mL}{1.475_M}$

$V_1=23.3~mL$

I hope it helps!

8 0

3 years ago