All categories

3 years ago

Lead will float in water.

2 answers:

7 0

Actually, no. While their mass may be the same (1kg), the volume of lead is a lot smaller than that of feathers. As there is the same mass stuffed in a smaller space, it must be denser. The density of water is 1 g/cm3, so if the density of the lead is more than 1g/cm3, it has to sink

Mandarinka [93]3 years ago

4 0

Yea, no sir :) guy above is on point.

You might be interested in

zzz [600]

Answer:

You should be posting this question under the biology tab, but here's the answer nonetheless.

a. 25% (if the woman is Ce)

c. 0% (if the woman isn't Ce)

5 0

3 years ago

the concentration of the radio active isotope potassium-40 in a rock sample is found to be 6.25%. what is the age of the rock

julsineya [31]

Answer:

5.0 x 10⁹ years.

Explanation:

It is known that the decay of a radioactive isotope isotope obeys first order kinetics.

Half-life time is the time needed for the reactants to be in its half concentration.

If reactant has initial concentration [A₀], after half-life time its concentration will be ([A₀]/2).

Also, it is clear that in first order decay the half-life time is independent of the initial concentration.

The half-life of K-40 = 1.251 × 10⁹ years.

For, first order reactions:

k = ln(2)/(t1/2) = 0.693/(t1/2).

Where, k is the rate constant of the reaction.

t1/2 is the half-life of the reaction.

∴ k =0.693/(t1/2) = 0.693/(1.251 × 10⁹ years) = 5.54 x 10⁻¹⁰ year⁻¹.

Also, we have the integral law of first order reaction:

kt = ln([A₀]/[A]),

where, k is the rate constant of the reaction (k = 5.54 x 10⁻¹⁰ year⁻¹).

t is the time of the reaction (t = ??? year).

[A₀] is the initial concentration of (K-40) ([A₀] = 100%).

[A] is the remaining concentration of (K-40) ([A] = 6.25%).

∴ (5.54 x 10⁻¹⁰ year⁻¹)(t) = ln((100%)/( 6.25%))

∴ (5.54 x 10⁻¹⁰ year⁻¹)(t) = 2.77.

∴ t = 2.77/(5.54 x 10⁻¹⁰ year⁻¹) = 5.0 x 10⁹ years.

8 0

3 years ago

Read 2 more answers

Give the mass percent of carbon in C14H19NO2?

Pachacha [2.7K]

72.0726 is the percent for carbon

7 0

3 years ago

Read 2 more answers

What is the chemical formula and net ionic equations for all three solutions.

timofeeve [1]

Answer:

See answer below

Explanation:

As you are asking for chemical formula and ionic equation, then, I will assume that after the station #4 below, are the solutions you are requiring.

You are also not specifing if you want for example, result of solution 1 + solution 3. If you need that, please post that on another question.

Now for the chemical formula, you need to identify the elements in all 3 solutions, and also the type of compound.

1. Solution 2 Potassium Chloride:

In this case we have Potassium on one side, and Chlorine on the other side, the symbol for those are K and Cl. As Potassium have the +1 oxidation state, cause is the only one that it can have, when it's next to an halide like chlorine or bromine, it will form a binary salt. The halides, usually work with the lowest oxydation state. In the case of Chlorine it will be -1, so, the formula will be:

KCl

And the net ionic equation will be the chemical equation that shows how the charges and atoms are balanced. In this case it would be:

K⁺ + Cl⁻ ------> KCl

2. Solution 1 Copper(II) sulfate:

In this case we have a tertiary salt, The copper's symbol is Cu, and is working with it oxydation state +2. Sulfate is an anion and it's formula is SO₄ and works with oxydation state -2 instead.

The chemical formula and ionic equation will be:

Copper(II) sulfate: CuSO₄

And the net equation:

Copper sulfate: Cu²⁺ + SO₄²⁻ -------> CuSO₄

3. Solution 3 Sodium hydroxide:

In this case, we have a compound that it's usually used in acid base reactions. This is a strong base or hydroxide, and we have the element of Sodium (Na) with the oxydation state +1, is the only one it can have, and for the other side we have the oxydrile anion OH, and together is working with the oxydation state -1. So the chemical formula will be:

NaOH

And the net ionic equation:

Na⁺ + OH⁻ -------> NaOH

Hope this helps

4 0

2 years ago

__ P4(s) + __ O2(g) → __ P4O10(s) To balance this reaction equation, first write correct formulas for the reactants and products

Vedmedyk [2.9K]

Answer:

P4(s) + 5 O2 (g)→ P4O10

Explanation:

If we desire to write a balanced chemical reaction equation, the rule of thumb is simple; the number of atoms of each element on the right hand side of the reaction equation must be the same as the number of atoms of the same element on the left hand side of the reaction equation. Once this condition is satisfied, the reaction equation is said to be balanced.

As we can see, we need one mole of P4 and five moles of O2 to produce one mole of P4O10.

8 0

3 years ago