Help!! 8th grade science (for a grade)

Answer:

Explanation:

The mass of a substance when given the density and volume can be found by using the formula

mass = Density × volume

From the question we have

mass = 25 × 3.26

We have the final answer as

Hope this helps you

The options are;

A) Carbon dioxide

B) Carbon Monoxide

C) Chloro fluoro carbon and methane

D) Refrigerant Freon

Answer:

B) Carbon Monoxide

Explanation:

Greenhouse gases are compounds available in the atmosphere which are capable of absorbing infrared radiation, thereby making heat in the atmosphere to be trapped and held there. The most common ones are carbon Monoxide, carbon dioxide, chloro-fluoro carbon, methane, nitrous oxide, ozone and freon. Out of them, the one that is the most dangerous and doesn't contribute to climate change is carbon monoxide because it is a silent killer gas

Thus, option B is correct

Answer:

The proportion of light transmitted by glazing is specified by the Visible Light Transmittance, which is recorded as either TVw (visible transmittance of the window) or VLT (visible light transmittance). These terms are interchangeable, but in Australia, the Window Energy Rating Scheme uses Tvw in its ratings.

While the VLT/Tvw rating varies between 0 and 1, most double glazed windows rate between 0.3 and 0.7 , which means that between 30% and 70% of the available light passes through the window. The illustration above shows you how the view changes, as the amount of light getting through the window changes.

Explanation:

Answer: 1s²2s²2p³ or it can also be 3s²2p³

Answer:

Beta decay is most common in elements with a high neutron to proton ratio. Gamma decay follows the form: In gamma emission, neither the atomic number or the mass number is changed. A high energy gamma ray is given off when the parent isotope falls into a lower energy state.

Explanation:

pls mark me as brainliest

Answer:

in terms of chemistry, the forward reaction balances the backward reaction :)

Explanation:

Answer: As we all are aware that life on Earth is existed due to several environmental changes and there are several scientific factors of sustainability that support the survival and evolution of life on Earth.

Scientific factors of sustainability include solar energy, chemical cycle, and biodiversity that supported life on Earth. solar energy helps all organism and especially producers to gain energy and store the energy which further used in chemical cycles of transferring energy to other trophic levels.

Chemical cycle also involves the interaction of biotic and abiotic envrionment with each other that leads to environmental changes as well as organisms adapt themselves accordingly.

Biodiversity maintains the balance in the ecosystem and prevent dominancy of one organism otherwise it can lead to scarcity and organism would not be able to survive. Variation in biodiversity due to random mating  in the same species leads to evolution and produces new species of organisms.  

Hence, scientific factors of sustainability play major role in survival and evolution of life on the Earth.

Explanation: Is this what you need

Answer:

Bro, its so obvious. Its electrical conductivity.

Explanation:

Plastic is an insulator thus it can protect conducting material from shortage of current as well for the safety of users. Thus, option 4 is correct.

Conductivity of a material is the measure of its ability to pass electric current through it. Based on this there are three types of materials namely conductors, insulators and semiconductors.

Conductors are materials highly conducting at room temperature. Semiconductors are not conducting at room  temperature but can be conducting at higher temperatures.

Insulators does not conduct electricity at any situation. Hence, insulators are used to coat conducting wires and to protect from electric shock. Plastic s an insulator which can cover conducting copper wire for safety. Thus, option 4 is correct.

Find more on conductivity:

https://brainly.com/question/15085692

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Answer:

Rate = K[NH₄⁺][NO₂⁻]

Explanation:

In kinetics studies of reaction, rate law is a mathematical expression that relates speed of reaction with concentrations of the reactants. For a reaction:

aA + nN → cC + dD

The rate law is expressed in terms of [A] and [B] as follows:

Rate = K[A]ᵃ[N]ⁿ

Where K is rate constant.

For the reaction:

NH4+ + NO2– ⟶ N2 + 2H2O

The rate law is:

As was said in the problem, the rate is porportional to [NH₄⁺] and to [NO₂⁻]

Answer:

The electronegativity difference of the atoms in the bond.

Explanation:

Carbon is electropositive while Oxygen is highly electronegative, hence highly polar due to strong intermolecular forces.

The molecule is not symmetrical because it's dipole moments don't cancel out.

Answer:

55.95K

Explanation:

its obtained from Q=MCT where

Q-amount of heat

M-mass of water

C-specefic heat capacity of water

T-change in temperature

Answer:

The boiling point of iodine is 363.7°F / 184.3°C

Answer:

New findings from NASA's Mars Reconnaissance Orbiter (MRO) provide the strongest evidence yet that liquid water flows intermittently on present-day Mars. Using an imaging spectrometer on MRO, researchers detected signatures of hydrated minerals on slopes where mysterious streaks are seen on the Red Planet. These darkish streaks appear to ebb and flow over time. They darken and appear to flow down steep slopes during warm seasons, and then fade in cooler seasons. They appear in several locations on Mars when temperatures are above minus 10 degrees Fahrenheit (minus 23 Celsius), and disappear at colder times.

Explanation:

Answer:

(4) sperm - transports genetic material

Explanation:

Which reproductive structure is correctly paired with its function'?

(1) uterus - usual site of fertilization

(2) testis - usual location for egg development

(3) ovary - delivers nutrients to the embryo

(4) sperm - transports genetic material

Solution:

The uterus (also known as the womb) is where the fertiled egg (foetus) stays until it is ready to be delivered. The usual site of fertilization  is the fallopian tube.

The testis is responsible for the production of sperm and hormones. The uterus is where the egg development takes place.

The ovary is responsible for the production of egg and hormones. The embryo receives nutrient through the fetus.

The sperm transports genetic material to the ovum.

Answer:

4

Explanation:

because ovaries def do not deliver nutrients to the embryo thats the placenta and the testis are DEF not a site for egg development and the uterus is not where fertilization happens i believe its where the fetus is kept and therefore the only correct answer is 4 :)

Answer:

The answer is 76.0944

Explanation:

I hope this helps!

The molar mass and molecular weight of C3H6(OH)2 is 76.0944.

Answer:

The water is the medium of the wave

Answer:

Sodium, Oxygen and Hydrogen

Explanation:

Na= Sodium

O= Oxygen

H= Hydrogen

Answer:

Mostly Metals, But hydrogen is the only one that isn't.

Answer:

A) [tex]6.5\times 10^{23}\ \text{molecules}[/tex]

Explanation:

m = Mass of water = 38.9

M = Molar mass of water = 18 g/mol

[tex]N_A[/tex] = Avogadro's number = [tex]6.022\times 10^{23}\ \text{mol}^{-1}[/tex]

The reaction of electrolysis would be

[tex]2H_2O(l)\rightarrow 2H_2(g)+O_2(g)[/tex]

Number of moles of [tex]H_2O[/tex]

[tex]n=\dfrac{m}{M}\\\Rightarrow n=\dfrac{38.9}{18}\ \text{mol}[/tex]

From the reaction it can be seen that 2 moles of [tex]H_2O[/tex] gives 1 mole of [tex]O_2[/tex]

So, number of moles of [tex]O_2[/tex] produced is

[tex]\dfrac{38.9}{18}\times \dfrac{1}{2}=1.081\ \text{mol}[/tex]

Number of molecules

[tex]1.081N_A=1.081\times 6.022\times 10^{23}\\ =6.5\times 10^{23}[/tex]

So, [tex]6.5\times 10^{23}\ \text{molecules}[/tex] of oxygen is produced.

Answer:

B

Explanation:

all living things are composed of one or more cells

Answer:

A

Explanation:

RMM of ca(c2h302)2=158

%Ca= 40/158×100=25.3

%C=48/158×100=30.3

%H=6/158×100=3.7

%O=64/158×100=40.5

Answer:

a) 25.3% Ca, 30.4% C, 3.8% H, 40.5% O

Explanation:

Molar mass of Ca(C₂H₃O₂)₂  = 158.160 g/mol

percent composition:

Ca = (40 /158.160 ) × 100

Ca = 25.3%

C = (48 /158.160 ) × 100

C = 30.4%

H = (6 /158.160 ) × 100

H = 3.8%

O = (64 /158.160 ) × 100

O = 40.5%

40.5% + 3.8% + 30.4% + 25.3% = 100%

It means 1st option is correct.

Answer: C

Explanation:

Answer:

Explanation:

The volume of a substance when given the density and mass can be found by using the formula

[tex]volume = \frac{mass}{density} \\[/tex]

From the question we have

[tex]volume = \frac{25}{0.8765} \\ = 28.52253...[/tex]

We have the final answer as

Hope this helps you

3.03 × 10²⁵ formula units KCl

Math

Pre-Algebra

Order of Operations: BPEMDAS

Chemistry

Unit 0

Atomic Structure

Step 1: Define

50.3 mol KCl (Potassium chloride)

Step 2: Identify Conversions

Avogadro's Number

Step 3: Convert

[tex]\displaystyle 50.3 \ mol \ KCl(\frac{6.022 \cdot 10^{23} \ formula \ units \ KCl}{1 \ mol \ KCl} )[/tex] = 3.02907 × 10²⁵ formula units KCl

Step 4: Check

We are given 3 sig figs. Follow sig fig rules and round.

3.02907 × 10²⁵ formula units KCl ≈ 3.03 × 10²⁵ formula units KCl

Answer:

C.

The pan will be the same temperature as the stove.

Explanation:

Answer:

arsenous acid

Explanation:

Answer:

neutron

Explanation

neutrons have no net charge

Answer:

ammonia water especially : the impure solution obtained as a by-product in destructive distillation (as of coal, tar, and bones)

Explanation:

Answer:

liquor ammonia is the ammonia water especially , the impure solution obtained as a by-product in destructive distillation (as of coal, tar, and bones)

Answer:

1. First, I would observe the fire and the conditions of the scene, looking for the origin of the fire and looking in an accelerant was used. If I could find the origin of the fire I would make sure to not have any evidence damaged, and if I could not find the origin of would look from other forms of evidence, like clothing, flammable liquids, or igniters.

2. Secondly, I would make sure to preserve the area, and document the scene, with pictures and notes and any other forms of recording. It is important to initiate permanent documenting of the scene.

3. Thirdly, I would try to find anything flammable with a snider, and run the tests on what it could be. It is also important to make sure everybody is safe, and to evaluate for any safety hazards. Finally, I would create safety zones and communicate the hazards to people near the scene.

4. I would next contact the incident commander, and also search for any evidence that says whether the fire was an accident or was arson. If the fire was arson, I would locate any evidence that could lead to suspects, and if the fire was an accident, I would try to find all the evidence that shows how it happened.

5. Once I collect all the evidence, I would organize it in the best way possible and then I would use the hydrocarbon method in order to test the evidence that I found.

6. After the results come back based on the evidence, I would compare the results with the information found about the fire security in the building, the people involved, and I would start in trying to solve the crime.