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3 years ago

How do scientists test their ideas?

Chemistry

2 answers:

sasho [114]3 years ago

4 0

The answer is c because scientists need to make there test is right

kolezko [41]3 years ago

3 0

It is <span>By controlling their experiments to isolate a single variable</span>. so B

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What volume of solution must be added to 4.0 mol of NaCl to make a 1.2 M solution?

Aleksandr [31]

Answer:

$\boxed {\boxed {\sf 3.3 \ liters}}}$

Explanation:

Molarity is a measure of concentration in moles per liter.

$molarity=\frac{moles \ of \ solute}{liters \ of \ solution}}$

The solution has a molarity of 1.2 M or 1.2 moles per liter. There are 4.0 moles of NaCl, the solute. We don't know the liters of solution, so we can use x.

molarity= 1.2 mol/L
moles of solute= 4.0 mol
liters of solution =x

Substitute the values into the formula.

$1.2 \ mol/L = \frac{4.0 \ mol}{x}$

Since we are solving for x, we must isolate the variable. Begin by cross multiply (multiply the 1st numerator and 2nd denominator, then the 1st denominator and 2nd numerator.

$\frac {1.2 \ mol/L}{1}=\frac{ 4.0 \ mol}{x}$

$4.0 \ mol *1=1.2 \ mol/L *x$

$4.0 \ mol = 1.2 \ mol/L *x$

x is being multiplied by 1.2 moles per liter. The inverse of multiplication is division, so divide both sides by 1.2 mol/L

$\frac{4.0 \ mol}{1.2 \ mol/L} = \frac{1.2 \ mol/L *x}{1.2 \ mol/L}$

$\frac{4.0 \ mol}{1.2 \ mol/L}=x$

The units of moles (mol) will cancel.

$\frac{4.0 }{1.2 } \ L =x$

$3.33333333 \ L=x$

The original measurements both have 2 significant figures, so our answer must have the same. For the number we found, this is the tenths place.

The 3 in the hundredth place tells us to leave the 3 in the tenths place.

$3.3 \ L\approx x$

Approximately <u>3.3 liters of solution</u> are needed to make a 1.2 M solution with 4.0 moles of sodium chloride.

7 0

3 years ago

What is the bond length of cubic close packing?

Oxana [17]

Answer:

1.5a

Explanation:

4 0

3 years ago

How many atoms are in each of the following molecules:A. CO2B. N2C. CHCOOH

zlopas [31]

<h2>Answer:</h2>

A) 3 atoms - 1 atom of Carbon and 2 atoms of oxygen.

B) 2 atoms of Nitrogen.

C) 6 atoms - 2 Carbon atoms, 2 Hydrogen atoms, and 2 Oxygen atoms.

<h2>Explanations:</h2>

A molecule is a group of atoms bonded together, representing the smallest fundamental unit of a chemical compound. Molecules are made up of atoms.

According to the following information, we are to find the number of atoms in the given molecules.

A) For carbon dioxide CO₂, this molecule is made of 3 atoms - 1 atom of Carbon and 2 atoms of oxygen.

B) For the compound N₂, this molecule is made up of 2 atoms of Nitrogen.

C) For the compound CHCOOH, this molecule consists of 6 atoms - 2 Carbon atoms, 2 Hydrogen atoms, and 2 Oxygen atoms.

4 0

1 year ago

8 DO

Goryan [66]

Answer:

Increased use of resources

Additional waste produced

More construction

Cutting down trees

3 0

3 years ago

Write the two balanced equations, one for the incomplete combustion of methane (to form carbon monoxide and water vapor), and an

kompoz [17]

Answer:

$2CH_{4(g)} +3O_{2(g)} -->2CO(g)+4H_{2}O_{(g)}\\CH_{4(g)} +2O_{2(g)} -->CO_{2(g)} +2H_{2}O_{(g)} \\$

Explanation:

$2CH_{4(g)} +3O_{2(g)} -->2CO(g)+4H_{2}O_{(g)}\\CH_{4(g)} +2O_{2(g)} -->CO_{2(g)} +2H_{2}O_{(g)} \\$

The incomplete combustion of alkanes, and other fuels actually, happens when there is a limited supply of oxygen. Instead of the fuel burning completely to produce carbon dioxide, it produces carbon monoxide instead.

This gas is harmful to jumans because it combines with haemoglobin in lood and takes up space that belongs to oxygen which can lead to suffocation or even death

6 0

3 years ago