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The number of grains of rice in the 40 mL sample : 880 grains

Given

from recorded data:

mass of 20 grains rice = 0.4 g

mass beaker = 29.5 g

mass beaker+rice=47.1 g

mass only rice = 17.5 g

Required

the number of grains of rice

Solution

Maybe if we use a digital scale with high resolution accuracy we can get the mass of 1 grain of rice

But we still use existing data

To determine the mass of rice in the beaker, we just need to find the difference between the mass of the beaker + rice - beaker, or we can set the scale to zero before we add rice to the beaker.

If we look at this difference, the mass of the rice in the beaker should be :

47.1-29.5 = 17.6 g

Since the data shows that 20 grains of rice mass 0.4 g, so 17.6 g of rice contains:

[tex]\tt 17.6~g\times \dfrac{20~grains}{0.4~g}=880~grains[/tex]

Answer:

a

Explanation:

Answer:

false

Explanation:

because elements never exist in nature as single isotopes they are always combined

Answer:

FALSE

Explanation:

in the cases of three elements (tellurium, indium, and rhenium) the most abundant isotope found in nature is actually one (or two) extremely long-lived radioisotope(s) of the element, despite these elements having one or more stable isotopes.

Answer:

No

Explanation:

There are vaccines, to prevent it, made by Dr. Fauci, but no cure

Answer:Yes I am very good at acid

Explanation:

Answer: I say  B

Explanation:

Answer:

False

Explanation:

Answer:

false

Explanation:

false

Answer:

The correct answer is B

Explanation:

Educere

aluminium + copper oxide → aluminium oxide + copper. Hence, option B is correct.

A word equation represents a chemical reaction using the names of the substances involved.

aluminium + copper oxide → aluminium oxide + copper correctly shows the word equation for the reaction of aluminium and copper oxide yielding aluminum oxide and copper.

Hence, option B is correct.

Learn more about word equations here:

https://brainly.com/question/2602833

#SPJ2

Answer:

292.1 kg = 292 100 g

Explanation:

n = m/Mm

Mm(Cu) = 63.5

m = n * Mm

m = 4.6 * 63.5

m = 292.1 kg

Answer:

I had this question and it was the 4th one for me

Explanation:

Answer:

Top left: RR Top right: Rr Bottom left: Rr Bottom right: rr

Explanation:

if both parents are heterozygous then the table will always look like this. the chances of the offspring being heterozygous are 50%. the offspring has a 25% chance of having two recessive traits and a 25% chance of having two dominant traits.

Answer:

Ovary

Explanation:

The ovaries are organs that lie to the upper right and left of the uterus. They produce, store, and release eggs into the fallopian tubes in the process called ovulation

Moles of Oxygen produced : 4.5 moles

A reaction coefficient is a number in the chemical formula of a substance involved in the reaction equation. The reaction coefficient is useful for equalizing reagents and products.

The reaction coefficient shows the mole ratio of the reactants and products

Reaction

2KCIO₃ → 2KCl + 30₂

moles of KCIO₃ = 3

From equation, mol ratio of KCIO₃ : O₂ = 2 : 3, so mol O₂ :

[tex]\tt mol~O_2=\dfrac{3}{2}\times 3=4.5[/tex]

Answer: 1.414 mol Cl-  

Explanation:

First, let's find the moles of BeCl2.

1.79 M = 1.79 mol/L

395 mL = 0.395 L , since 1L = 1000 mL

Using stoichiometry,

1.79 mol/L *0.395 L = about 0.707 mol BeCl2

Now, we have 0.707 mol of BeCl2, but we are trying to find moles of Cl-

There are two chloride ions in each molecule of BeCl2, so there will be twice as many moles as well.

0.707 mol BeCl * (2 mol Cl- / 1 mol BeCl) = 1.414 mol Cl-  

Hope this helps!

Answer:

Decantation

Explanation:

Decantation is a process for the separation of mixtures of immiscible liquids or of a liquid and a solid mixture such as a suspension.

Answer:

In acetic acid, due to the +I effect of the alkyl group the electron density on the oxygen atom increases.

The release of H + ion becomes difficult. Thus , greater the magnitude of +I effect weaker will be the acid.

Order of +I effect : CH 3>H

Therefore , formic acid (HCOOH) is more acidic than acetic acid (CH 3COOH).

Answer:

1.4 mol

Explanation:

that my i got i was doing for it

Answer:

hydrogen ions which is H+

Answer: An acid is a solution with more H+ ions than OH- ions. An acid is any compound that yields hydrogen ions (H+) or hydronium ions (H3O+) when dissolved in water.

Explanation:

Answer:

0.45881381335

Explanation:

divide 45 by the molar mass of H2SO4

45/98.079

Answer:

0.45

Explanation:

divise

Answer:

Pure solids or liquids are excluded from the equilibrium expression because their effective concentrations stay constant throughout the reaction. The concentration of a pure liquid or solid equals its density divided by its molar mass.

Explanation:

Hope this helps!!!

its me again this is how you find the answer. note: i dont have the periodic table to see the exact atomic mass to find the molar mass however this is the answer:

so the actual formula is Mg(OH) with a 2 as a subscript because there are 2 Mg. so with Mg(OH)2 the Molar mass is 58.32g/mol. 58.32 g/mol x 7.1x1024 = 4.1x1026g

Answer: 272.5915639999...

Explanation: