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Pepsi [2]
3 years ago
14

Girls are usually completely physically mature by _____ years old.

Chemistry
2 answers:
fomenos3 years ago
6 0

Answer:

17

Explanation:

edge 2020 i just took the topic test

krok68 [10]3 years ago
5 0

Answer:

a 17 bc it is how it works

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7. Lli(s) + N₂(g) → 2 Liz Ncs)
timurjin [86]

The number of mole of lithium, Li needed for the reaction is 3.2 moles (Option D)

<h3>Balanced equation </h3>

4Li + N₂(g) → 2Li₂N

From the balanced equation above,

2 moles of Li₂N were obtained from 4 moles of Li

<h3>How to determine the mole of lithium needed </h3>

From the balanced equation above,

2 moles of Li₂N were obtained from 4 moles of Li

Therefore,

1.6 moles of Li₂N will be obtained from = (1.6 × 4) / 2 = 3.2 moles of Li

Thus, 3.2 moles of Li are needed for the reaction

Learn more about stoichiometry:

brainly.com/question/14735801

8 0
2 years ago
20cm³ of methane gas was burnt in 20cm³ of oxygen. write a balanced chemical equation for the reaction and determine which of th
solniwko [45]

Answer:

CH4 +O2 => CO2 + 2 H2O

None were in excess

Explanation:

Equation for the reaction is,

CH4 + O2 =>CO2 +2 H2O

No of moles of CH4 = (20 /1000)/24 =0.02 /24 = 0.00083

No of moles of O2 =20 /24000 = 0.0083

CH4 : O2 = 1:1

THEREFORE

None of the gases were in excess.

7 0
3 years ago
Air bags are activated when a severe impact causes a steel ball to compress a spring and electrically ignite a detonator cap. Th
Sedaia [141]

Answer:

154 g

Explanation:

Step 1: Write the balanced decomposition equation

2 NaN₃(s) ⇒ 2 Na(s) + 3 N₂(g)

Step 2: Calculate the moles corresponding to 79.5 L of N₂ at STP

At STP, 1 mole of N₂ occupies 22.4 L.

79.5 L × 1 mol/22.4 L = 3.55 mol

Step 3: Calculate the number of moles of NaN₃ needed to form 3.55 moles of N₂

The molar ratio of NaN₃ to N₂ is 2:3. The moles of NaN₃ needed are 2/3 × 3.55 mol = 2.37 mol.

Step 4: Calculate the mass corresponding to 2.37 moles of NaN₃

The molar mass of NaN₃ is 65.01 g/mol.

2.37 mol × 65.01 g/mol = 154 g

6 0
3 years ago
Base your answer on the information below. in liquid water, an equilibrium exists between h2o() molecules, h+(aq) ions, and oh–(
kicyunya [14]

Answer:

OH^-

Explanation:

Any substance that is able to neutralize acidity in the stomach is generally known as an antacid. There are various kinds of antacids that are in common use. It should be noted that the stomach is usually slightly acidic.

Milk of magnesia is the substance magnesium hydroxide with chemical formula Mg(OH)2. A solution of milk of magnesia contains Mg^2+ and OH^-.

Hence the negative ion contained in milk of magnesia is the hydroxide ion  OH^-.

8 0
2 years ago
How many particles are in 23 g of H 2 O?
Sedaia [141]
1 mole of any substance contains 6.022 × 1023 particles.

⚛ 6.022 × 1023 is known as the Avogadro Number or Avogadro Constant and is given the symbol NA

N = n × NA

· N = number of particles in the substance

· n = amount of substance in moles (mol)

· NA = Avogardro Number = 6.022 × 10^23 particles mol-1


For H2O we have:

2 H at 1.0 each = 2.0 amu
1 O at 16.0 each = 16.0 amu
Total for H2O = 18.0 amu, or grams/mole

It takes 18 grams of H2O to obtain 1 mole, or 6.02 x 1023 molecules of water. Think about that before we answer the question. We have 25.0 grams of water, so we have more than one mole of water molecules. To find the exact number, divide the available mass (25.0g) by the molar mass (18.0g/mole). Watch how the units work out. The grams cancel and moles moves to the top, leaving moles of water. [g/(g/mole) = moles].

Here we have 25.0 g/(18.0g/mole) = 1.39 moles water (3 sig figs).

Multiply 1.39 moles times the definition of a mole to arrive at the actual number of water molecules:

1.39 (moles water) * 6.02 x 1023 molecules water/(mole water) = 8.36 x 1023 molecules water.

That's slightly above Avogadro's number, which is what we expected. Keeping the units in the calculations is annoying, I know, but it helps guide the operations and if you wind up with the unit desired, there is a good chance you've done the problem correctly.

N = n × (6.022 × 10^23)


1 grams H2O is equal to 0.055508435061792 mol.

Then 23 g of H2O is 1.2767 mol


To calculate the number of particles, N, in a substance:

N = n × NA

N = 1.2767 × (6.022 × 10^23)

N= 176.26

N=
3 0
2 years ago
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