Chemistry, please help

Answer:

Explanation:

Radioactive decay follows the equation:

Ln [A] = -kt + ln [A]₀

Where [A] is amount of isotope after time t: Our incognite,

k is rate constant: ln 2 / Half-life = 0.0231 years⁻¹

t are 60 years

[A]₀ is initial amount of isotope: 1.0g

Replacing:

Ln [A] = -kt + ln [A]₀

Ln [A] = -0.0231 years⁻¹*60 years + ln 1.0g

ln [A] = -1.386

[A] = 0.25g

Answer:

sugar dissolving in water

Explanation:

at the end mixing 2 substances and not get a new substance is not a chemical change. the sugar is still sugar even when its in water.

Answer: You could use the process of distillation, which involves boiling the substance.

Explanation: The component that boils at the lowest temperature will become a vapor and separate.

Answer:

B. CO2 + H2O

Explanation:

Propane is an hydrocarbon as it contains only v=carbon and hydrogen atoms.

Whenever an hydrocarbon reacts with oxygen or undergoes a combustion reaction, two products are always formed only,

These two products are;

Carbon dioxide (CO2) and water (H2O)

This means the correct option is option B.

Answer:

31 N left and 32 N right because

Explanation:

It’s the only one movement because when you subtract them there’s still 1 left

Answer:  Savanna, Woodland, or Grassland.

Giraffes eat new shoots and leaves, their habitat needs to have a good supply of trees -- they flock towards acacia trees in particular. Giraffes use their extremely long legs, necks and tongues to browse mainly from the thorns on the acacia tree. The tongue and the inside of the mouth are lined with tough tissue that protects against the thorns.

Answer:

red supergiants is the answer

Eating fewer processed foods would promote the development of more-sustainable practices in the world food system.

This is the food which has undergone some degree of alteration during preparation such addition of preservatives etc.

Eating less of it will ensure that more sustainable practices in the world food system are promoted.

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Answer:

Input work is the work done on a machine as the input force acts through the input distance. This is in contrast to output work which is a force that is applied by the body or system to something else. Output work is the work done by a machine as the output force acts through the output distance.Jan 15, 2020 bahsgsh bvshgs d hg

Answer:

The correct answer is - brand of floor wax.

Explanation:

The independent variable is the variable or the factor in an investigation which is manipulated or change in the experiment and affects the dependent variable and produces a various result.

In this investigation, there are different brands of the floor was are the independent variable as they are changed to see the effect on the scratches on the floor on 20 tiles for each brand.

Answer:whjwjehd

Explanation:

Answer:

sal5 water = kaka

Explanation:

because i need points ty man

Answer:

I'm sorry, we need the image to answer  it.

Explanation:

Answer:

Explanation:

NCl3 does not dissolve in water because it is a nonpolar molecule which is different with water. NCl3 is nonpolar due to the difference in electronegativities between 3 atoms of Cl and 1 atom if N2.

Answer:

A polar solute dissolves into a polar solvent and a non-polar compound dissolves into a non-polar solvent, this rule is known as "like dissolves like".

Answer:

fsdafdsafdsafdsafdasfsagfd

Explanation:

Answer:

as soon as the pollen reaches the stigma after the pollen grain descends down the style when the pollen tube grows into the ovule when the seed germinates

Explanation:

B. velocity

This is the answer

Answer:

Monosaccharides, these are the simplest building block of carbs

Explanation:

Answer:

The first option: Strontium Fluorate.

Explanation:

because Fluorine and oxygen combines to make fluorate, Strontium stays the same.

p.s: i need help in geo and there's an exam tomorrow.

Answer:

5 moles

Explanation:

Given data:

Number of moles of HCl = 5 mol

Number of moles of H₂O produced = ?

Solution:

Chemical equation:

HCl + NaOH     →   NaCl + H₂O

Now we will compare the moles of HCl with H₂O.

                          HCl            :           H₂O

                             1               :             1

                             5               :            5

5 moles of water will be produced.

Answer:

b

Explanation:

I think B because its saying that perhaps watering with salt water would make them grow faster, you don't know yet unless tested.

In the given unbalanced reaction, the number of sodium is not balanced. There must have two sodium in the product side also. The correct formula of sodium sulphate is Na₂SO₄.

According to the law of conservation of mass, the total mass of a system is conserved. Thus, mass can neither be created nor be destroyed. Therefore, for a chemical reaction, the total mass in the product side must be equal to the total mass in the reactant side.

The balanced equation of  a chemical reaction thus, obeying the mass conservation law where, each element have to be equal in number in both sides.

In the given reaction, the number of Na in reactant side is 2 and that in product side is 1 only. Thus total mass of sodium is not conserved. It can be corrected as Na₂SO₄ in the product side.

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Answer:

oh my god i have learnt about this

Explanation:

Answer:

Point A

Explanation:

I dont know why but it was right on the test.

Answer:

the amount of matter in the bowling ball remains the same

Explanation:

The reason why the mass of the bowling ball on earth and moon remains the same is that matter in the bowling ball remains the same.

Mass of any substance is the amount of matter it contains.

Answer:

energy goes into the chemical and cool downs the surrounding area.

Answer:

The dependent variable is the number of clams developing from fertilized eggs.

The independent variable is the water temperature

The optimum temperature for clam development is 30 degrees centigrade.

Explanation:

The graph of the number of clams developing from fertilized eggs and water temperature is attached to this answer.

The independent variable is being manipulated in an experiment. As it changes, it produces a corresponding change in the dependent variable.

Here, the water temperature is the independent variable. As it changes, the number of clams developing from fertilized eggs (dependent variable) also changes alongside.

The optimum temperature is the temperature at which the greatest number of clams developing from fertilized eggs is produced. We can see from the graph that this temperature is 30 degrees centigrade.

Answer:

Explanation:

The force acting on an object given it's mass and acceleration can be found by using the formula

force = mass × acceleration

From the question we have

force = 80 × 1.6

We have the final answer as

Hope this helps you

[tex]\huge\boxed{5.1x[tex]10^{14}[/tex]Hz}[/tex]

E = [tex]3.38 x 10^{-19}[/tex]

h = [tex]6.625x10^{-34}[/tex]

f = ?

Energy of Photon is given by,

                                   E = hf

Rearrange the equation,

                                    f = [tex]\frac{E}{h}[/tex]

where,

           E = energy

           h = planck's constant

           f = frequency

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Substitute the variable in the equation,

                                 f = [tex]\frac{3.38x10^{-19}}{6.62x10^{-34}}[/tex]

Simplify the equation,

                                  f = 5.10 x 10^14 Hz          

Answer:

b. 5.10 x 10^14 Hz

Explanation: