How many protons and neutrons in the atom K-42

Who no this i need help i need to pass to the next grade

Hitman42 [59]

Exothermic reactions is where energy is released. Exothermic reactions are reactions that release energy into the environment in the form of heat. Exothermic reactions feel warm or hot or may even be explosive.

7 0

3 years ago

Which substance is a base? HCOOH RbOH H2CO3 NaNO3

Alex Ar [27]

Answer:

RbOH

Explanation:

For this question, we have to remember what is the definition of a base. A base is a compound that has the ability to produce hydroxyl ions $OH^-$ , so:

$AOH~->~A^+~+~OH^-$

With this in mind we can write the reaction for each substance:

$HCOOH~->~HCOO^-~+~H^+$

$RbOH~->~Rb^+~+~OH^-$

$H_2CO_3~->~CO_3^-^2~+~2H^+$

$NaNO_3~->~Na^+~+~NO_3^-$

The only compound that fits with the definition is $RbOH$ , so this is our base.

I hope it helps!

6 0

3 years ago

Read 2 more answers

An exponent of "2" means that if we double the concentration of the reactant the rate doubles as well Exponents in rate laws are

Karo-lina-s [1.5K]

Answer:

- False.

- True.

Explanation:

Hello, for each statement we state:

- An exponent of "2" means that if we double the concentration of the reactant the rate doubles as well.

FALSE because considering a rate law like:

$-r=kC^2$

The exponent of "2" powers the concentration to the second power, not doubles the rate law, thus, if C is 3, for k=1, r will be -9. On the other hand if the rate is like:

$-r=kC$

The rate will be -3, that is why the rate is not doubled when the "2" in concentration is present.

- Exponents in rate laws are based on the coefficients from the balanced equation.

FALSE because for nonelemental chemical reactions, the exponents do not match with each species' stoichiometric coefficients in the rate law.

- The rate constant, k, takes into account the effect of activation energy and temperature on the reaction.

TRUE, since the Arrhenius equation allows us to prove the effect of the activation energy and the temperature:

$k=Aexp(-\frac{Ea}{RT})$

- Differential rate laws allow us to compare concentration and time.

TRUE as they are given like:

$\frac{1}{\nu _A} \frac{dC_A}{dt} =\frac{1}{\nu _B} \frac{dC_B}{dt} =...$

Best regards.

5 0

3 years ago

Statements

allochka39001 [22]

1. Make an observation : My toaster doesn't toast my bread

2. Ask a question : Why doesn't my toaster work?

3. Form a hypothesis : My coffeemaker works when plugged into the outlet

4. Make a prediction : If something is wrong with the outlet, then my coffeemaker also won't work when plugged into it

5. Conduct an experiment : I plug my coffeemaker into the outlet

6. Analyze the results : There is something wrong with the electrical outlet

Explanation:

The solution to the problem is as shown above.

A scientific method follow a methodical way of critically carrying out an inquiry into an observation.
Firstly, an observation is usually made with our senses. Here the researcher observes that the toaster does not toast his bread probably after a long wait.
He then proceeds to ask why the toaster does not work.
To investigate this, the forms a hypothesis. A hypothesis is a scientific guess. It is a tentative proposition about an investigation.
The researcher then makes a prediction about the outlet that might be faulty.
With this background, he goes on to carry out an experiment to substantiate his findings. This is seen when he plugs the coffeemaker into the outlet.
From the analysis of result, he sees that that something is wrong with the outlet.

Learn more:

purpose of experiment brainly.com/question/5096428

#learnwithBrainly

7 0

3 years ago

What is the chemical equation for the alpha decay of erbium-144

iren [92.7K]

Answer:

Er-144 -------> Dy-140 + He-4

Explanation:

Alpha decay is the release of a hydrogen nucleus. So the original atom will decrease the mass by 4 and the atomic number by 2.

8 0

3 years ago