In biology class, we had to______ the parts of a plant cell under a microscope.

Answer:

The 3R rule states that cracks tend to form at a (n) right angle on the opposite side from the point of impact.

Explanation:

Answer:

The answer is "0.38 A".

Explanation:

Please find the missing image file in the attachment.

In the given image let:

[tex]R_{12} =R_1+R_2=16 \ \Omega \\\\R_{34} =R_3+R_4=20 \ \Omega \\[/tex]

[tex]R_P=\frac{R_{12} \cdot R_{34}}{R_{12} +R_{34}}[/tex]

     [tex]= \frac{16 \cdot 20 }{16 +20}\\\\= \frac{320 }{36}\\\\= \frac{80 }{9}\\\\= 8.88 \ \Omega[/tex]

similarly,

[tex]R_{eq} =R_p+R_5+R_6\\\\[/tex]

      [tex]=8.88+24+20\\\\=52.89 \ \Omega \\\\[/tex]

calculating the current value through a switch:

[tex]\to I=\frac{V}{R_{eq}} = \frac{20 \ v}{52.89 \Omega }=0.38\ A[/tex]

Answer:

D. 0.38 amperes

Explanation:

Got it correct on Gizmos

Gizmos explanation: This compound circuit contains two parallel branches connected in series to 2 more resistors. Each parallel branch contains 2 resistors in series. The resistance of the first branch is 5+11=16 ohms, and the resistance of the second branch is 20 ohms. Using the equivalent resistance formula, the resistance of this section is

1R=116+120=580+480=980

So R is 809, or 8.89 ohms. This is connected in series to a 24-ohm and a 20-ohm resistor, for a total resistance of 52.89 ohms. The battery voltage is 20 volts, so by Ohm's law

I=VR

I=2052.89=0.38amperes

Answer:

Kinetic; attraction; attraction.

Explanation:

Kinetic energy can be defined as an energy possessed by an object or body due to its motion.

Mathematically, kinetic energy is given by the formula;

[tex] K.E = \frac{1}{2}MV^{2}[/tex]

Where, K.E represents kinetic energy measured in Joules.

M represents mass measured in kilograms.

V represents velocity measured in metres per seconds square.

Conduction involves the transfer of electric charge or thermal energy due to the movement of particles. When conduction relates to electric charge, it is known as electrical conduction while when it relates to thermal energy, it is known as heat conduction.

In the process of heat conduction, thermal energy is usually transferred from fast moving particles to slow moving particles during the collision of these particles. Also, thermal energy is typically transferred between objects that has different degrees of temperature and materials (particles) that are directly in contact with each other but differ in their ability to accept or give up electrons.

Hence, as the temperature of a substance increases, the average kinetic energy of the particles also increases, and movement overcomes forces of attraction more easily. As temperature decreases particles move more slowly and the attraction-forces between particles dominate.

In conclusion, when a substance or an object is heated, a phase change starts to occur only when the average kinetic energy of its particles is great enough to overcome the force of attraction between its particles.

Answer:

O Each orbit has a specific energy level.

Explanation:

Neils Bohr put forward his own model of the atom based on the quantum mechanics originally developed by Planck.

He assumed the Rutherford's model and suggested that the extranuclear part consists of electrons in specific spherical orbits around the nucleus.

The orbits/energy level are the permissible through which the electrons can move through.

His concept is based the concept that the electron can move round the nucleus in certain permissible orbitss

Answer:

d. 10 million years

Explanation:

These are the options for the question

Choose one answer.

a. 2.5 million years

b. 5 million years

c. 15 million years

d. 10 million years

✓half-life of the radioactive substance= 5 million years

✓ Then for every 5 million years, original radioactive given (100%) percentage is reduced by factor of 1/2.

✓ 1st 5 million year; After the first 5 million years, the original radioactive is reduced as;

(100%) × 1/2 = 50% remains

✓2nd 5 million year: At 10 millions year, the 50% remaining radioactive is reduced by factor of 1/2

(50%) × 1/2 = 25% remains

Hence, at At 10 millions years 25% of the original radioactive atoms remain

.

Answer:

10 million years

The empirical formula :

C₁₀H₁₆N₄SO₇

Given

6.4 g sample

Required

The empirical formula

Solution

mass C :

= 12/44 x 8.37 g

= 2.28

mass H :

= 2/18 x 2.75 g

= 0.305

mass N = 1.06

mass S :

= 32/64 x 1.23

= 0.615

mass O = 6.4 - (2.28+0.305+1.06+0.615) = 2.14 g

Mol ratio :

= C : H : N : S : O

= 2.28/12 : 0.305/1 : 1.06/14 : 0.615/32 : 2.14/16

= 0.19 : 0.305 : 0.076 : 0.019 : 0.133 divided by 0.019

= 10 : 16 : 4 : 1 : 7

The empirical formula :

C₁₀H₁₆N₄SO₇

Answer:

C2H2

Explanation:

Mass of Carbon in CO2[tex]= (12/44) (20.31)[/tex] grams [tex]= 5.54[/tex] gram

Mass of hydrogen in H2O [tex]= (2/18)(4.26)[/tex] grams [tex]= 0.46[/tex] gram

We will calculate the % of C and H in the sample  

% C [tex]= (5.54/6) * 100 = 92[/tex]%

% H [tex]= (0.46/6)*100 = 7.7[/tex]%

Number of mole of C [tex]= 92/12 = 7.69[/tex]

Number of mole of H [tex]= 7.67/1 = 7.67[/tex]

Fractional share of  C [tex]= 7.69/7.67 = 1[/tex]

Fractional share of  H [tex]= 7.67/7.67 = 1[/tex]

Empirical Formula = CH

Empirical Mass [tex]= 12+1 = 13[/tex]

Molecular mass [tex]= 26[/tex]

Molecular Formula – CHn  

N [tex]= 26/13 = 2[/tex]

Molecular Formula = C2H2

Answer: 1.67

D=M/V

(D=57.4/34.3)= 1.67

Answer:

a) 24.7 mol

b) 790 g

Explanation:

Step 1: Given data

Step 2: Convert "T" to Kelvin

We will use the following expression.

K = °C + 273.15

K = 23°C + 273.15 = 296 K

Step 3: Calculate the moles (n) of oxygen

We will use the ideal gas equation.

P × V = n × R × T

n = P × V/R × T

n = 3.00 atm × 200. L/(0.0821 atm.L/mol.K) × 296 K = 24.7 mol

Step 4: Calculate the mass (m) corresponding to 24.7 moles of oxygen

The molar mass (M) of oxygen ga sis 32.00 g/mol. We will calculate the mass of oxygen using the following expression.

m = n × M

m = 24.7 mol × 32.00 g/mol = 790 g

Answer:

C) tellurium (Te) is the correct answer.

Answer:

B.nitrogen

Explanation:

Nitrogen is a gas at room temperature.

Answer:

The answer is below

Explanation:

The unit cell edge length (a) = 0.298 nm = 0.289 * 10⁻⁷ cm

The unit volume (V) = a³ = (0.289 * 10⁻⁷ cm)³ = 24 * 10⁻²⁴ cm³

There are 2 atoms per cell, hence N = 2. Also, [tex]n_a=avogadro\ constant=6.02*10^{23}\ mol^{-1}[/tex]

[tex]atomic\ weight\ of\ iron(A_f)=55.85,atomic\ weight\ of\ vanadium(A_V)=50.94,[/tex]

[tex]density\ of\ iron(\rho_f)=7.87,density\ of\ vanadium(\rho_v)=6.1.\\\\V=\frac{nA_{av}}{n_a\rho_{av}} \\\\A_{av}=\frac{100}{C_v/A_v+C_f/A_f} \\\\\rho_{av}=\frac{100}{C_v/\rho_v+C_f/\rho_f} \\\\C_v=concentration\ of\ vanadium,C_f=concentration\ of\ iron.\\\\V=\frac{nA_{av}}{n_a\rho_{av}}=\frac{n*\frac{100}{C_v/A_v+C_f/A_f}}{n_a*\frac{100}{C_v/\rho_v+C_f/\rho_f}}\\\\[/tex]

[tex]24*10^{-24}=\frac{2*\frac{100}{C_v/50.94+C_f/55.85}}{6.02*10^{23}*\frac{100}{C_v/6.1+C_f/7.87}}\\\\7.2=\frac{C_v/6.1+C_f/7.87}{C_v/50.94+C_f/55.85}\ \ \ (1) \\\\Also:\\\\C_v+C_f=100\%\ \ \ (2)\\\\\\solving\ equation\ 1\ and\ 2\ simultaneously\ gives:\\\\C_v=10\% \ and\ C_f=90\%\\\\[/tex]

Answer:

Greatly affect.

Explanation:

This level of fishing will greatly affect the populations of the other fish in the simulated reef because overfishing disturbs the equilibrium in the marine ecosystem. One fish is a food of another fish or the big fish act as a controller which controls the population of other small fishes and in that way the ecosystem is present in equilibrium state so overfishing will greatly affect the marine ecosystem.

its dry i think

Explanation:

it might be dry

Answer:

0.48g

Explanation:

Given parameters:

Mass of zinc  = 15g

Unknown:

Mass of hydrogen gas = ?

Solution:

To solve this problem, we need to state the balanced reaction expression first;

          Zn   +   2HCl   →   ZnCl₂    +   H₂

Find the number of moles of Zn;

    Number of moles  = [tex]\frac{mass}{molar mass}[/tex]    = [tex]\frac{15}{63.4}[/tex]    = 0.24mol

From the balanced reaction expression;

             1 mole of Zn will produce 1 mole of H₂  

            0.24mole of Zn will produce 0.24mole of hydrogen gas

Mass of hydrogen gas  = number of moles x molar mass

                                      = 0.24 x (2 x 1)

                                      = 0.48g

Answer:

Black

Explanation:

Answer:

the answer is

-there is the same number of each type of atom on the right side of the equation as the left.

Explanation:

i have study island too :')

Answer:

i think its oxide not too sure

Answer:  

 Its should be ammonium chloride.

A picture to help you with another question like this

Answer:  On Earth, liquid water exists on the surface in the form of oceans, lakes and rivers. It also exists below ground as groundwater, in wells and aquifers. Water vapor is most visible as clouds and fog. The frozen part of Earth's hydrosphere is made of ice: glaciers, ice caps and icebergs.

Answer:

Via covalent bonds

Explanation:

Atoms in molecules are bonded together via covalent bonds. Covalent bonds are bonds that are formed by sharing of the valence electrons between two atoms.

The atoms can be of the same kind or of different kinds.

Answer:

its burning

Explanation:

can you please try to answer my latest question i need it badly please and thank you

Answer:

Burning.

Explanation:

Example:

Wood burns and produces smoke and ash.

Answer:

h3po2

Explanation:

Answer:

i think it is H3PO4

Explanation:

Answer:

[tex]d=7.77\times 10^{13}\ m[/tex]

Explanation:

We know that the speed of light is equal to [tex]3\times 10^8\ m/s[/tex]

We need to find how far the light travel in 3 days.

Speed of an object is equal to distance covered divided by time taken.

Also, 1 day = 86400 s

3 days = 259200 s

So,

[tex]d=vt[/tex]

[tex]d=3\times 10^8\times 259200\\\\d=7.77\times 10^{13}\ m[/tex]

So, the light will travel [tex]7.77\times 10^{13}\ m[/tex] in 3 days.

Answer:

-1

Explanation:

According to this question, the oxidation state/number of H and O in C2H4O is +1 and -2 respectively.

The oxidation state of carbon in the compound can be calculated thus:

Where;

x represents the oxidation number of C

C2H4O = 0 (net charge)

x(2) + 1(4) - 2 = 0

2x + 4 - 2 = 0

2x + 2 = 0

2x = -2

Divide both sides by 2

x = -1

The oxidation number of C in C2H4O is -1.

Answer:

Explanation:

-We convert Ca(OH)₂ grams to moles using its molar mass:

-We convert K₂SO₃ moles to grams using its molar mass:

-One formula unit of HCl is HCl. We convert molecules to moles using Avogadro's number:

-At STP, one mol of any gas occupies 22.4 L:

Answer:

well heat travels by conduction, convection, and radiation but I think it's 2.

Explanation:

heat travels to colder things trying to make a balanced temperature for both of the objects.

Answer:

C₂ =  0.52 M

Explanation:

Given data:

Initial volume = 334.75 mL

Initial concentration = 1.28 M

Final volume = 822.18 mL

Final concentration = ?

Solution:

C₁V ₁     =     C₂V₂

By putting values,

1.28 M×334.75 mL = C₂×822.18 mL

C₂ =  1.28 M×334.75 mL / 822.18 mL

C₂ =  428.48 M.mL / 822.18 mL

C₂ =  0.52 M

Answer:

80g/mol is the molar mass of the metal

Explanation:

A divalent metal M reacts with HCl as follows:

M + 2HCl → MCl₂ + H₂

The excess of HCl is titrated with NaOH. Thus, we can solve the moles of HCl that reacts with the metal and the moles of the metal. As the atomic weight is the ratio between the mass and moles of the atom:

Moles NaOH:

0.0546L * (0.22mol / L) = 0.0120 moles NaOH = Moles HCl in excess

For NaOH and HCl solutions, Normality is the same than molarity.

Moles HCl added:

0.100L * (1.28mol / L) = 0.128 moles HCl * (50mL / 200mL) = 0.032 moles

Moles HCl in that react:

0.032 moles - 0.012 moles = 0.020 moles HCl

Moles M:

0.020 moles HCl * (1mol M / 2 mol HCl) = 0.010 moles M

Molar mass M:

0.8g / 0.010mol =

Answer:

The arguments both for and against allowing genetically altered meats into the United States is explained below in details.

Explanation:

Arguments for and against genetically altered meats:

Answer:

The arguments both for and against allowing genetically altered meats into the United States is explained below in details.

Explanation:

Arguments for and against genetically altered meats:

Supply the Society. By 2050, the world's inhabitants are supposed to increase from today's 7 billion to way beyond 9 billion.

ENVIRONMENTAL RISK.

STRONGER CROPS = LESS PESTICIDES.

REMEMBER WHEN CIGARETTES WERE 'HARMLESS'?

TAMPERING FOR TASTE. ...

BIG BUSINESS EATS SMALL FARMERS.

ENHANCED HEALTH.

NOTHING TASTES BETTER THAN NATURE.

Explanation:

Answer:

B. The temperature of the water when the food sample has finished burning completely.

Explanation:

Heat or thermal energy is a form of energy that transfers from one object to another due to a temperature difference between the objects. The units for heat are joules or calories.

Calorimetry is the measurement of heat energy released or absorbed in a chemical  reaction. A calorimeter is used in calorimetry. The calorimeter operates on the Law of Conservation of Energy which states that energy is never created or destroyed but is transformed from one form to another or between objects.

In food calorimetry, the energy released when food is burned is measured by recording the rise in temperature of water in a calorimeter when a given mass of a food sample is burned completely.

Energy can be calculated using the formula: Q = mc ∆T

where Q = the energy in joules or calories, m = the mass in grams, c = specific heat and ∆T = the change in temperature (final temperature - initial temperature).

The temperature of the water when the food sample has finished burning completely is taken as the final temperature of the water. The sample is allowed to smolder for sometime before recording the final  water temperature. This is because the water temperature will continue to rise after the  flame has gone out.